Nanotec AFM Letters - Nanotec Electronica

nanotecafmlettersnanotec newsThe best AFM trainingPage 17The easiest-to-use AFM withWSxM Page 9FM-AFMTrue atomic resolution in liquidsPage 18

Editorial informationnanotec afm letters is published by Nanotec Electronica S.L.Centro Empresarial Euronova 3, Ronda de Poniente 12, 2ºC. 28760 Tres Cantos, Madrid. Spain.Tel. +34-91 804 33 26 // Fax. +34-91 804 33 48.For any question please contact at: sales@nanotec.es

Dear friend of Nanotec,Mr. Rafael FernandezNanotec General ManagerAfter many years of developments, we have finally released WSxM3.0, and launched the new WSxM 5.0 version. We have great plansfor this new version of our software, and we hope that you will continuesupporting us with your feedback to keep developing the best SPMsoftware.As you probably know, the world economical situation has affected the science community.To face this point, Nanotec has launched a new idea which can help the finances of the AFM researchersin the world: After detecting that there are many scientists with old, bad, or even not workingcontrollers for potentially useful AFM heads, we have developed a cost-effective solution to “rejuvenate”those heads, by connecting them to our powerful Dulcinea controller. The power of WSxM’smicroscope control part will be this way helping your old head to get cutting-edge data again (findmore information in page 28).Also, our R&D department has been working, in collaboration with the highest level SPMlaboratories (see Acknowledgements), in many new features, including software developments,new AFM heads, new options, etc. In order to get you to know the new developments we are involvedon, we have launched this magazine, which I hope will be interesting for everybody. We havetried to organize the developments in the index in different sections, starting with those that youcan already use for free if you just upgrade your software. Second, we have indexed those that arepossible additions to your Cervantes FullMode AFM, then we have listed those useful if you own aDulcinea for controlling a third-party AFM/STM, and finally those that are interesting to you if youown a non-Nanotec AFM, and would like to add some of these new developments to it.The presented developments are in different state of evolution, so please contact us forquestions about any of them. Also, we continue with our “open developments” policy, so if you finda development that is interesting in this list, remember that we can offer you a prototype so yoy willbe among the first ones to enjoy it, and if you do not find the feature you would like, let us knowand we will evaluate the possibility of including it in our plans or collaborating with you in order tomake it possible.3

free improvements forall nanotec usersnew modesFrequency Modulation.............................8Easy-to-use WSxM................................9General Spectroscopy Imaging(acquiring volumes of data)...................10Nanomanipulation.................................11Atom Tracking........................................11new / improved featuresGeneric Curves acquisition...................12Cantilever K estimation.........................12Automatic Drift correction......................13XY Tilt....................................................13Friction decoupling...............................14Real-time view of amplitude, phase, X,and Y......................................................15indexcervantes fullmodeafm new optionsnew modulesWSxM Gold Package............................17Lanza AFM Head.................................18High Vacuum AFM/STM........................20Variable field MFM...............................20Variable temperature............................21continues on the next page >>Top image: Integrated circuit imaged with closed-loop. Nanotec Electrónica S.L.5

cervantes fullmodeafm new optionsscannersClosed loop...........................................22XY inertial scanners..............................22Ultra long scanner.................................23improved modulesDual lock-in (KPM, multifrequency, harmonics,etc)...........................................232 MHz bandwidth..................................24Large samples......................................24Variable gain IV.....................................25dulcinea controllernew optionsDLPCA-200 compatibility.....................27dI/dV module.......................................27Laptop control......................................27other spm mechanics´ownersInertial Box...........................................293rd party interfaces..............................29reference list..........................................30acknowledgements............................32free improvements forall nanotec usersSince the creation of Nanotec Electronica, our software department have been working to providethe SPM comunity with the most flexible and complete SPM softwares. WSxM is a user-friendly,reliable and powerful tool to study samples at the nanoscale and provide new insights into the capabilitiesof the SPM technique for data acquisition and processing.During the last few years, Nanotec has been looking for new and more advanced features toimprove the functionality of WSxM and provide the best solutions to our customers.The latest developments introduced here will expand the possibilities of your Cervantes AFM andDulcinea Electronics and will provide new solutions to your research.Upgrade now your WSxM Software (www.nanotec.es) to the last WSxM 5.0 Develop version andstart enjoying the latest Data Acquisition (with Nanotec Cervantes FullMode AFM or Dulcinea Controlleronly) and Processing SPM features from today.6Top image: Dulcinea electronics7

Frequency ModulationBecause Ultra High Vacuum (UHV) requires much greater controlthan ambient conditions, the standard dynamic modes are notaccurate enough. Therefore Nanotec has integrated the FrequencyModulation technique as a possibility in the Dulcinea Controlsystem. For this mode of operation, three feedbacks should be closedand stabilized simultaneously. Also, very fine resolution is neededfor working in the lowest possible amplitudes. The differentdynamic mode menus of WSxM have been adapted to the possibilityof performing Frequency Modulation, and now our users areapplying it not only in UHV, but also in ambient conditions and liquidsso they can get much better results.Topographic UHV NC-AFM image of theSi(111) 7x7 surfaceMorita Lab. Osaka Univ. JapanEasy-to-use WSxM: WSxM adquisition WizardAt Nanotec, we are always focusing in offering not only the best quality products, but also the bestuser experience. In that direction, we combine the continuous addition of new options and features,with the continuous upgrade of the software interface with the goal of getting it as easy to use aspossible. With that aim, we have added the option of linking P,I parameters, the automatization of XYgains, improvements in changes of Z gain for avoiding any possibility of crashing the tip, and advancedsections in many of the menus to separate those parameters rarely used from those that aremore important in each menu.Also, we have added automatic calculation of scales in the channels, and automatic search for an initialset point in the approach.In addition, we are developing a new one-click one-image interface, which will make the acquisitionof an image with WSxM as simple as the creation of a data DVD for the beginners. Of course, thatwill not mean the lack of options, as the user will always be able to switch to the classic interface forusing the full set of features that WSxM provides.Sample: octadecylamine (18 carbon atoms, linear)deposited on mica by immersion in a solution 15 mMin chloroform, dried and aged for several weeks.Images courtesy of J.J. Benitez Institute of MaterialsScience of SevilleTrue atomic resolution in liquids. Mica(001) Author: David Martínez - Martin andJulio Gómez. New Microscopies Lab.(UAM)The new Wizard of the Full-Mode Cervantes AFM willallow to easily aquire animage in less than 15 minutesfrom scratch89

General Spectroscopy Imaging(acquiring volumes of data)With the new General Spectroscopy Imaging menu, you will be able to perform any kind of spectroscopymaps over your image. This includes volumes of any magnitude you can measure with yourDulcinea controller, like force, current, or frequency drift. The usual freedom of choice you find inother Nanotec modes is specially interesting in this mode, allowing you to measure any volume youcan think about, selecting even the shape of the spectroscopy curve. Due to the complexity of theacquired data, a full set of data processing options has also been developed for its proper treatment.NanomanipulationOne of the main differential features of AFM isthe capability to interact with the surface that isbeing measured, in order to create changes atthe choice of the researcher. At Nanotec, wehave recently developed a Nanomanipulationmenu, that allows interactive and fast nanomanipulationby presenting an informative graphicalinterface, which indicates the effects of youractions in the monitored signal in every moment,as well as allows you the fast executionof custom designed lithographic scripts. Usingthis menu, we hope you will be able to fullycontrol your nanomanipulation experiment forthe fast creation of the structures you need.Atom TrackingA new menu for Atom Tracking has been developed.This feature was required for UltraHigh Vacuum experiments, in order to ensurethat the studies of the interaction between theAFM tip and a particular atom were always performedin the same place above the atom. It isalso a perfect system for fast drift calculation.The atom tracking technique is based on thedisplacement of the tip in circles around the selectedatom, calculating and following its movement.After its development in collaboration with theUniversity of Osaka, we encourage all Cervantesusers to apply it to ambient conditionsexperiments. In principle, this concept wouldbe applicable to any quasi-spheric object, regardlessof its size.Screen capture showing the data processof a Force Volume. Experiment on a virus.Author: Carolina Carrasco. NewMicroscopies Lab. UAMFinal topographic NC-AFM image of the process of lateral manipulationof substitutional Sn adatoms in the Ge(111)-c(2x8) surfaceat room temperature. Morita Lab. Osaka Univ. Japan.Movement of the tip during Atom Tracking experiment. Trackingresolution: +/-0.2Å Test performed by Sugimoto in Morita LabOsaka Univ. Japan.1011

Generic Curves acquisitionIt is very important for AFM to extract one dimensional spectroscopy data. So, any AFM will allow theuser to perform Force vs. Distance curves (FZ), Current vs. Distance curves (IZ) and Current vs.Voltage curves (IV). At Nanotec we decided not to limit the spectroscopy experiments to those standardmeasurements, but to leave it completely open. So, besides the specialized menus for acquiringthe standard spectroscopy curves, we have developed the Generic Curves Acquisition menu, whichallows the performance of any spectroscopy experiment, varying one magnitude (between the 12available including 3 rear user output BNCs) and recording other magnitude (between the 16 availableincluding the 4 rear user input BNCs). This allows performing a huge number of combinations, includingfor example, Phase vs. Excitation Frequency curves.Cantilever K estimationAutomatic Drift correctionAn inherent problem to Scanning Probe Microscopy is thethermal drift. Temperature variations at the microscope environmentcause a small drift between the tip and the sample.Even with the Nanotec piezoelectric scanners, carefully designedto minimize the drift, this effect is a problem that affectsthe measurements and makes them less accurate than theyshould be.From long ago, in the Nanotec systems, the user had thepossibility of correcting drifts during movie acquisition. Everytimea new image was acquired, the drift was calculated, andcompensated before starting with the next image. This methodhas shown very good results allowing many hours of videoeven with atomic resolution in Ultra High Vacuum environments.Drift correction menu accessIn order to convert the forces read by the system into physical units(nN/pN), it is necessary to provide the cantilever force constant (K) tothe system. Before this development, the user supplied this informationbased on the data from the cantilever manufacturer or from his own estimations.The data given by the manufacturer usually has too large anerror, which makes it useless for precise force measurements, and theestimations are tedious for the user without software assistance.So, after some discussion in the NanotecForum, it was suggested thatthe Sader method was a nice estimation. The Nanotec software teamthought it was a nice idea to facilitate its use to WSxM users, and madethe necessary development so estimation of the cantilever K is now aneasy thing.Force calibration menu (including K estimation) Cantilever Nanosensor of 40 N/mRecently, Nanotec has expanded the possibilities of the driftcorrection in several ways. First, we have created a new menuthat allows activating the drift correction in any moment (notonly during the acquisition of movies); second, using the capabilitiesof Dulcinea, we have included Z drift correction, allowingto use the highest resolution gain for long times; and third, we have developed continuous XYdrift correction, correcting the drift even inside the image or during spectroscopy experiments.XY TiltIn very controlled environments, like Ultra High Vacuum (UHV) at Low Temperature, in which thereis not movement of the atoms, sometimes it is useful to stop the scan, remove the feedback thatkeeps the tip-sample distance constant, and move the tip over the sample dynamically, interactivelyand fast. This possibility was partially there in Nanotec systems, as you could stop the scan, stop thefeedback, and move the tip with the mouse, but it was not as useful as it should because of thesample tilt.12 13

With XY tilt correction, the WSxM softwarecalculates the tilt of your sample in order totake it always into account. As soon as WSxMcorrects it, the system will start working in thesame way as if there was not any tilt betweenthe sample surface and the XY movement ofyour scanner, so you will be able to move freelyover the surface with the mouse without caringabout the sample inclination.This correction is also useful for systems inUHV or ambient conditions (without Low Temperature),not for removing the feedback(which is not recommended in general), but forsmoothing the feedback work, as it will not seethe tilt, and will be better in following the realobjects on the surface easily without the needof changing the scan angle.Auto-tilt adjustmentFriction decouplingIt is well known that the AFM allows themeasurement of the friction of the tip with thesample. This is very useful for chemicaldistinction and for friction studies at thenanoscale. For detecting the friction, the AFMuses a four-quadrant photodiode, that separatesNormal Force and Lateral Force (see figureabove). The horizontal displacement of thelaser with respect to the photodiode indicatesthe torsion of the cantilever, which is directly relatedto the friction between the tip and thesample.As the alignment of the mechanical componentsworking in the measurement (laser, cantileverand photodiode) will never be 100%perfect, a part of the normal force (usually ordersof magnitude higher than the lateral force)will be induced in the lateral forcemeasurement. Nanotec has developed a processto calculate this error and to correct it inreal time, so the user can measure the frictionfree of any coupling.Coupling of theNormal Force andthe Lateral ForceReal-time view of amplitude, phase, X, and YSame experimentafter decouplingFor working in dynamic modes, we use an internal lock-in in Dulcinea (the Dynamic Force ModulationBoard) to separate the X and Y components of the incoming signal (usually normal force), and thenwe tune the frequency and phase of the lock-in, so we work in the resonance frequency, and X representsthe amplitude and Y the phase.This assumption (X=amplitude; Y=phase) is correct for small variations in the resonance frequencyof the cantilever when approaching to the sample. As usually there are, the mostecommended optionis to use the PLL (“Phase Lock Loop”) mode for frequency shift correction. The PLL mode will changethe working frequency in order to be always in resonance, and making the phase (Y) equal to zero.Up to now, the user could only see X and Y components, but for working in Amplitude Modulationmode without PLL, it is sometimes interesting to be able to map also the real Amplitude and Phase,as well as to feedback the system in Amplitude instead of X. We have recently improved WSxM software,so you can have the four signals simultaneously mapped in real time, and you can save themall together. This feature also expands for the second dynamic board, allowing the most fundamentalexperiments about the dynamic modes.14 15

WSxM Gold PackageIn 1998, Nanotec Electronica launched the first version of WSxM software. At that moment, we decidedto let WSxM free for downloading for our users, so they could update to the new developmentsat any moment, but also for anyone wanting to use the WSxM software for data process in public researchapplications. Our development team has also kept a constant effort in adapting WSxM to beable to read any SPM file format that has been appearing from then on. This approach, together withthe high quality of the software, has made WSxM the most popular SPM data processing softwarein the world.cervantes fullmode afmnew optionsNanotec Cervantes FullMode Atomic Force Microscope (AFM) is a cost-effective tool widely used tocharacterize samples and perform experiments at the nanoscale. Its various configurations allow notonly imaging samples with atomic precision but also the study of magnetic, electronic and mechanicalproperties at the nanoscale, making it a powerful tool for physicists, chemists, biologists andengineers willing to characterize their samples.Its robust design provides strong mechanical stability to ensure high imaging resolution, and its semiautomatedand open design allows scientists to exploit the capability of SPM to its maximum for bothresearch and academic purposes. It has been widely used in applications ranging from the study ofbiologic molecules in a liquid environment to the study of magnetic domains in a hard disk or themeasurement of conductivity of carbon nanotubes.Cervantes FullMode AFM is under continuous development to offer the best solutions and widen therange of applications available. Nanotec Electronica has implemented innovative AFM modules thatwill allow Cervantes users to add new features to the existing experiments.But during this time we learned that there was frequentlya lack of training for the new usersapproaching WSxM, which would be important towork on. For this reason, we have developed aset of videos for learning both abouth the basicsof SPM and about the principles of WSxM. We joinedthis development with a license allowing theuse of WSxM for profit applications, creating thisway the WSxM Gold Package, with the hope thatit will help WSxM users and SPM trainers.WSxM Gold Package.WSxM Tutorial: Multiple Dynamic ZoomWSxM Gold PackageA Primer on SPM hosted by Prof. Ron ReifengerderWSxM Gold Package. WSxM Tutorial: Multiple profileTop image: Integrated circuit imaged with closed-loop. Nanotec Electrónica S.L.16 17

Lanza AFM HeadThis new AFM head prototype foresees as the next step for Nanotec AFM headtechnology. Improving the quality and stability of the laser to reach 12 μm spot sizeon the cantilever, with an easier to use, and even increased mechanical stabilityagainst the standard Nanotec AFM head design, the results of the first prototypehave been much better even than expected, obtaining the highest resolution imagesof biological samples, as well as very nice atomic periodicity in air and true atomicresolution in liquids.Lanza Head First Prototypeand the atoms obtained in liquidsInterview with David Martínez:The roadwork to obtain true atomic resolution in liquidsThe new AFM head design, which is the result of a collaboration between David Martinez-Martinand Julio Gomez-Herrero with Nanotec, comes to the fore as the next stepfor Nanotec AFM technology. With this new prototype and Dulcinea control unit Davidhas been able to obtain state of the art (see results of Hirofumi Yamada’s and AndreasEngel’s groups) images of mica (001) in liquids with true atomic resolution.Question: How do you get this kind of high resolution images?Answer: I work with a technique which is called Frequency Modulation (FM-AFM or just FM). It is avery well known mode to work in vacuum but currently it is starting to be a very promising mode alsoin liquids.Question: When and why did you start to use Frequency Modulation?Answer: I started about three years ago, at the beginning of my PhD. As a first step of my PhD I builtup the first high vacuum system in Spain with an AFM inside. Due to the low pressure (high vacuum)the damping of the cantilever is very small which implies high Q factor and high sensitivity. The darkside are long transients when the cantilever amplitude changes, that makes difficult to obtain imagesusing the classical amplitude modulation, much easier to use in terms of electronic and software requirements.FM uses the frequency as the main feedback parameter and utilizes an amplitude feedbackto avoid the ringing associated to the high Q. This issue makes FM a more proper method thanthe standard amplitude modulation (AM) mode for high vacuum. As I said, one of the advantages ofworking in vacuum is that the sensitivity of an AFM is much higher than in air, for this reason I usethis system to study with high sensitivity long range interactions at the nanometer scale.Question: When did you decide to make the big jump from vacuum to liquids?Answer: A liquid environment is the common media for a big range of biological systems and I havebeen always very interested on these kind of systems. On the other hand, the New Microscopy Laboratorieshad extended experience doing biophysics with AFM, so we thought it could be interestingto combine the experience of Carolina Carrasco and Pedro Jose de Pablo in biology and my expertisein FM. And now I can say that it was a very successfulidea!.Question: Why does FM work so good in liquids?Answer: First of all I would like to clarify that,even though FM is the regular way to measurein vacuum, that does not mean at all that thistechnique is not appropriate for air ambientconditions or liquids. Actually this way to workgives you much more control on the relevantparameters of AFM than standard techniques,but it requires more and more complexfeedback systems and also a biggerknowledge about how to operatethe AFM. For instance, instead ofthe single feedback loop that isused in conventional amplitudemodulation or contact mode, FMneeds three feedback loops.If your question is why FM allowsto reach true atomic resolution inliquids what I can say is that the answeris still under discussion, but probablyit is related with the fact that the lowquality factor of the cantilever in liquids issomehow compensated for the screening ofVan der Waals forces due to the liquid. This togetherwith a small oscillation amplitude of thecantilever (much smaller than oscillation amplitudein Ultra high Vacuum) allows to detectshort range interactions.Question: You collaborated with Nanotec inthe construction of the vacuum AFM, and thenalso with the new Lanza head. Were you neverafraid of working on a prototype microscope?Answer: On the contrary, both times it was excitingto set up a unique system. I knew it wasmore difficult and risky, but it was also moresatisfying. These projects have a lot of partsand just one person is not able to do everything.The collaboration of Nanotec was fundamentalfor me, and finally the result deservesthe efforts.Question: After the experience of collaboratingwith Nanotec, what is your impression?Answer: I consider very important to performapplied research in the University. The systemsthat we have developed together withNanotec will not only allow me to performthe experiments that I need formy research, but they will soonhelp many other researchersworldwide. I will be very happy tocontinue collaborating with Nanotec.Question: Finally, what otherpeople helped you to obtain suchnice results?Answer: I have to thank to many peoplethat helped me during these years. Ofcourse Julio Gomez-Herrero, who is my PhDadvisor and the person who taught me all thesecrets about AFM along with Cristina Gomez-Navarro. I also learnt a lot about FM during mytime in Germany thanks to Franz Giessibl, oneof the leading persons in the field of AFM. Thetime that I spent in the laboratory of Julio Fernandezat Columbia University in NYC and inthe laboratory of Miquel Salmeron in Berkeleywas very important as well. I also would like tothank to Mariano Carrion, who introduced meto the world of bio AFM, and finally I would liketo thank to Pilar Iñiguez de la Torre, whocheered me up a lot and helped me to startthese projects.David Martínez is Ph. D. student in the New Microscopies Laboratory (NML) of the Madrid Autonoma University (UAM).Top image: Mica (001) Author: David Martínez - Martin and Julio Gómez. New Microscopies Lab. (UAM)18 19

High Vacuum AFM / STMWhen needing to work in clean or dryenvironments, like for highest resolution electrostaticmeasurements, the environmentalcontrol available inthe Cervantes AFMcould be not enough,and vacuum environmentcould be needed.Working invacuum has severalHigh Vacuum System.Nanotec Electronica S.L.clear advantagesagainst working inambient conditions:the quality factor (Q)of the cantilever increasesnaturally, offeringmuch higherresolution in dynamic modes; the liquid layerpresent always in ambient conditions disappears,allowing more precise studies of electrostatic,magnetism or adhesion; and finally theenvironment is much cleaner, so you do nothave to worry about your sample getting dirtywith dust particles during long time measurements.The cleanest environment for such problemsis the Ultra High Vacuum (UHV), but it iswell known that UHV systems are big, expensiveand complex, and require extensive tediousmaintenance work, combined with a longtime for sample / tip changing.In Nanotec Electronica, we have designed thebest midway solution: An affordable High VacuumAFM / STM, based on the Cervantesmini-platform FullMode AFM, that allowsreaching 10 -5 torr regime in about 15 minutes.Variable Field MFMNanotec Cervantes AFM has always been especiallysuitable for Magnetic Force Microscopy(MFM) studies, but it has been alwaysbased on measuring the magnetic propertiesof the sample without external applied magneticfield. Now, we have designed a new modelof MFM, which allows the study of the magneticresponse of the samples while applyingdifferent magnetic fields.The new Variable Field MFM allows applyingtwo different kinds of magnetic fields: perpendicularto the sample, or parallel to the sample.The new design with amagnetic componentsallows maintaining the highest stability and resolutionof Cervantes AFM. Combined with thedrift control possibilities of WSxM, it gives youthe power to study the dynamics of the magnetization/ demagnetization process with themaximum precision.Variable Field System. Nanotec Electrónica S.L.Variable temperatureFor many experiments, it is good to heat the sample in a controlled way, in order to understand theproperties of the sample at different temperatures. For SPM, it is important to be extremely carefulwhen heating the sample for several reasons: the heat could increase the thermal drift to a level inwhich the images are not reasonably good, the heat could affect the piezoelectric components, anddepolarize them, so the system would stop working, and the heat could affect the sticky material thatis used to keep the different components of the AFM together, causing it to malfunction.At Nanotec Electronica, we have designed a new add-on for temperature control, which allows thechange of temperature from ambient temperature up to more than 150ºC, varying it simultaneouslyin the tip and the sample, minimizing the thermal drift and with a design that isolates the piezoelectric.Nanotec Variable Temperature System20 21

Closed loopThe SPM technology is based on the use of piezoelectric material, which is deformed almost linearlywith a given voltage. This incomplete lineality is especially noticeable near the borders of the scanarea of the scanner, and shows up in severaleffects, like the distortion of the image or theinaccuracy when zooming to a smaller regionfrom a bigger one. At Nanotec Electronica wehave designed a closed-loop system, compatiblewith the previous hardware (for CervantesAFM and Dulcinea users). Based onthe use of strain gauges, the closed-loopmeasures the real displacement of the piezoscanner,correcting all the problems derivedfrom that piezo non-linearity. Its high resonancefrequency, humidity resistance and fiabilitymakes it the best option for accuratemeasurements, especially under liquid environment.Open LoopClosed LoopIntegrated circuit imaged without closed-loop and with closed-loop. Thedifferences in non-linearity are easily appreciated, mainly in the bordersof the scan areaUltra Long ScannerEven though the AFM technique is normally used for measuring small surfaces, everyday it is morecommon to find applications in which the capabilities of SPM are useful for bigger surfaces. So, wehave reviewed the design of our long scanner (70 µm) thinking in these applications, reaching to anew model that, in the first prototypes, was scanning more than 140 µm in opened loop and morethan 100 µm in closed loop operation.Dual lock-in (KPM, multifrequency, harmonics, etc)We have developed a complementary Dynamic Force Modulation Board.This board is clock-synchronized with the first one, allowing the performanceof dual frequency experiments. This means that while the firstlock-in is getting data in the resonance frequency of the cantilever, thesecond lock-in can be working at a completely different frequency,allowing multifrequency experiments, lock-in in harmonics or in a completelydifferent frequency as it is needed for Kelvin Probe Microscopy (KPM)experiments, that allow to know the local surface potential on the sample.XY inertial scannersSimple XY tip-sample positioning is an important issue if you want toposition the tip over a particular place of the sample, which you canlocate with optical microscopy. If your experiments require ambientcontrol, you will also need a system that can be controlled with software.Nanotec Electronica has designed a new model of scanners,compatible with any Dulcinea-based Nanotec AFM.This new model of scanners allows sub-micron precision positioningof the tip in any position of the sample, with full control in WSxM.Coarse XY motion menuThinking of KPMexperiments, weWSxM EFM / KPM Menuhave developeda special menu with the necessary automaticadjustments to start measuring as fast aspossible, without the need to adjust all thepossible parameters before starting themeasurement, but starting with a good suggestionfrom the software and then fine tuningthe parameters for the needs of theparticular experiment.KPM in Self Assembled Monolayer (SAM)M.Paradinas, L.Garzón, C.Munuera, C.Ocal “Combined Scanning ProbesInvestigation of SAM-based Heterogeneously functionalized surfaces”. Institutde Ciencia de Materials de Barcelona (ICMAB-CSIC)22 23

2 MHz bandwidthThe bandwidth of the AFM is very important forseveral applications. On one hand, the cantilevermanufacturers are increasing the resonancefrequency of their cantilevers, and onthe other hand, studies at harmonics or otherhigher frequencies are getting popular. So, forall the new customers of Nanotec Electronica,we will increase the bandwidth of the systemto 2MHz from the current 1MHz bandwidth.Large samplesNanotec Large Samples stageVariable gain IVFor measuring local conductivity on the surfaces, it is necessary to apply a voltage difference betweenthe tip and the sample, and to measure the current flowing through an IV converter. The design ofthe Nanotec cantilever holder is prepared for bias voltage application by default, but the measurementof the current requires an add-on which is the IV converter. We wanted a new IV model, optimizedfor current mapping and allowing a good set of available gains. The old model from Nanotec wasgetting the current from the sample through the piezo, to be converted in voltage in the IV electronics,attached to the platform of the microscope, and with fixed gain.One of the improvements in the new model is to allow gain selection.The new Variable Gain IV converterfeatures a set of four software selectable gains, allowing a bigger range of current to be measured,and the finest resolution for low currents. The second improvement was to design a specificsample holder for conductivity, that avoiding to wire the signal together with the piezo signals, allowsthe measurement of current maps with the highest quality.Frequency Spectrum of a Silicon Cantilever (k = 40 N/m)HOPG Image acquired in Dynamic Mode with a Silicon Cantilever(K = 40 N/m) oscillating at its 2nd oscillation modeIn Nanotec Electronica we know that sometimesthe maximum stability of the most compactdesign is not compatible with measuringall kinds of samples we would like to measure.As we got the request from a few of our customersto measure samples bigger than thepossible sizes for the standard Cervantes AFM(1 x 1 x 0.3 inches), wehave designed new AFMmodels making it possibleto increase the lateralsize up to 3 inchesdiameter and the maximumheight of the sampleup to 1 inch. Afterthat, we have ensuredthe stability, by using ourstandard atomic periodicityquality control.Nanotec Large SamplesAFM headNanotec Variable-Gain IV converterMetallic La 0.7 Sr 0.3 MnO 3 (LSMO) thin films grown by a chemical solutiondeposition (CSD) process on a SrTiO 3 substrate. These films havebeen developed through a new process leading to insulating epitaxial(Sr,La)Ox nanodots at the surface.Images courtesy by: C.Moreno, M. Paradinas, C.Munuera, X.Obradorsand C. Ocal. Institut de Ciència de Materials de Barcelona ICMAB-CSIC24 25

Dulcinea controllernew optionsDLPCA-200 compatibilityDLPCA-200 is a very popular IV used extensivelyby researchers using Ultra High VacuumScanning Tunneling Microscopy. We have developedan easy and user-friendly interface, soDulcinea users can work easily with this IV,using WSxM to select between all its options.Variable-Gain Low Noise Current Amplifier DLPCA-200dI/dV moduleConductance (dI/dV) maps are a very populartechnique between STM users. Up to now, forperforming dI/dV maps, you needed an externallock-in, and interfacing it with the Dulcineaelectronics. After several tests, we found outthat the Dynamic Force Modulation Board(standard for AFM) is also very useful for STMusers, allowing them to easily perform conductancemaps, simultaneously with the topographyand current.The flexibility and power of Dulcinea Control System is based on the combination of Dulcinea Electronicsand the M6701 Innovative Digital Signal Processor, all controlled by the powerful WSxM SPMSoftware.Dulcinea Control System forms the core of the versatility of Cervantes FullMode AFM, allowing manydifferent modes of operation from Jumping Mode to Phase Lock Loop (PLL) or Lithography, but ithas also proven to be a robust and powerful Control System not only for Cervantes AFM but also forother SPM systems available in the market.We introduce herein Nanotec new developments for all Dulcinea users, which will increase evenmore the versatility of your SPM system. The new Dulcinea modules will specially benefit those willingto get the most of their STM and UHV-STM system.Laptop ControlDynamic Force Modulation BoardFor some environments, it can be extremely useful to have a versatile AFM that can be easily movedfrom one location to another. Up to now, that meant moving a standard computer, which is heavyand difficult to transport together with the other components of the AFM. We have found out the wayto control the microscope using a laptop computer, reducing the logistic problems for these applications.26 27

Other SPMmechanics ownersThe open arquitecture and modular design of Dulcinea Electronics facilitates interfacing with anyother AFM/SNOM/STM system available in the market providing not only a huge range of measuringmodes (from contact mode to nanomanipulation or Frequency Modulation) but also the high precisionand quality required for Ultra High Vacuum experiments.Nanotec will study the technical requirements of your SPM head and will advise of the best solutionto guarantee full compatibility between Dulcinea Control System and your SPM system.Inertial BoxMost Ultra High Vacuum SPM systems basetheir coarse tip-sample motion in an inertialslip-stick mechanism: the application of a softvoltage ramp, followed by an immediate returnto the initial voltage generates an effective andrepetitive tip-sample movement that is neededfor the tip-sample approach or other large movements(in the range of tens of mm) inside theUHV chamber.We have designed and developed a UniversalInertial Box that, with 7 BNC ouputs, allows interfacingeasily the Dulcinea controller with anyUHV SPM system controlling up to 7 differentmovements.3rd party interfacesNanotec interfaces for VeecoIn the same way we have adapted WSxM toread file formats for any SPM in the market, wehave also developed interfaces for being ableto use WSxM to control any SPM head that wehave been requested to. Our electronics departmentis always happy to receive new requeststo connect Dulcinea to any home-madeor third-party SPM head.Nanotec universal inertial boxNanotec Interface for Omicron28 29

eference list(bibliography)GSI“DNA molecules resolved by electrical double layer force spectroscopyImaging” J. Sotres et al. Appl. Phys. Lett. 93, 103903 (2008)Lithography“WSXM: A software for scanning probe microscopy and a toolfor nanotechnology”, I. Horcas et al., Rev. Sci. Instr. 78, 013705 (2007)“Site-controlled lateral arrangements of InAs quantum dots grown on GaAs(001) patternedsubstrates by atomic force microscopy local oxidation nanolithography” J Martín-Sánchezet al, Nanotechnology 20 (2009) 125302“Single Photon Emission from Site-Controlled InAs Quantum Dots Grown onGaAs(001) Patterned Substrates”, J. Martín-Sánchez et al., ACS Nano, vol. 3, no 61513–1517 (2009)Nanomanipulation“Atom inlays performed at room temperature using atomic force microscopy”, Y. Sugimotoet al., Nature Materials, 4, (February 2005).Frequency Modulation“Enhancing dynamic scanning force microscopy in air: as close as possible”, E. Palacios-Lidónet al., Nanotechnology 20 (2009) 085707KPM“Surface potential domains on lamellar P3OT structures”, B. Pérez-García et al., Nanotechnology19 (2008) 065709“Probing Local Electronic Transport at the Organic Single-Crystal/Dielectric Interface”. Yi Luo et al.Adv. Mater. 0000,00, 1-7 (2007)Drift correction"Surface diffusion of Pb single adatoms on the Si (111)-( 3 x 3 )R30º -Pb system". I. Brihuega,M. M. Ugeda, and J. M. Gómez-Rodríguez. Physical Review B 76, 035422 2007."Direct Observation of a (3 x 3) Phase in Alpha-Pb/Ge (111) at 10 K". I. Brihuega, O. Custance, M.M. Ugeda, N. Oyabu, S. Morita, and J. M. Gómez-Rodríguez, Physical Review Letters 95, 206102(2005)Conductivity“Tuning the conductance of single-walled carbon nanotubes by ion irradiation in theAnderson localization regime” C. Gómez-Navarro et al., nature materials, 4, (July 2005)“Scanning force microscopy three-dimensional modes applied to conductivity measurements throughlinear-chain organic SAMs”, C. Munuera et al., Nanotechnology 18 (2007) 125505VF-MFM“Variable-field magnetic force microscopy”, M. Jaafar et al., Ultramicroscopy 109 (2009) 693–699“Field induced vortex dynamics in magnetic Ni nanotriangles”, M. Jaafar et al., Nanotechnology 19(2008) 285717“Remanence of Ni nanowire arrays: Influence of size and labyrinth magnetic structure” J. Escrig etal., Phys. Rev. B 75, 184429 (2007)K estimation“Frequency response of cantilever beams immersed in viscous fluids with applications to the atomicforce microscope”, J. E. Sader, J. Appl. Phys. 84 64 (1998).“Quantitative electrostatic force microscopy on heterogeneous nanoscale samples”,E. Palacios-Lidón et al., Appl. Phys. Lett. 87, 154106 (2005)30 31

AcknowledgementsNanotec wants to thank all those researchers who collaborate with us in the development of our AFM,giving us feedback and reasons for new challenges. In particular, for the developments appearing inthese pages we acknowledge to the following research groups and individual researchers: J. Abad(Murcia University), M. Abe (Osaka University), A. Asenjo (ICMM-CSIC), A. Baró (ICMM-CSIC),I. Brihuega (UAM), F. Briones (IMM-CNM-CSIC), C. Carrasco (UAM), I. Casuso (University ofBarcelona), V. Chab (Inst. of Physics AS CR), F. Chandezon (CEA Grenoble), O. Cheshnovsky (TelAviv University), J. Colchero (Murcia University), O. Custance (NIMS), P. de Pablo (UAM), I. Díez-Pérez (University of Barcelona), L. Fumagalli (University of Barcelona), F. Fuso (Pisa University), J.M. García ((IMM-CNM-CSIC), R. García (IMM-CNM-CSIC), J. Gómez-Herrero (UAM), C. Gómez-Navarro (UAM), M. Gómez-Rodriguez (UAM), G. Gomila (University of Barcelona), L. González (IMM-CNM-CSIC), Y. González (IMM-CNM-CSIC), P. Gorostiza (University of Barcelona), G. Gramse(University of Barcelona), B. Grevin (CEA Grenoble), M. Hernando (UAM), M. Jaafar (ICMM-CSIC),A. Kuhnle (Osnabrück University), M. Luna (IMM-CNM-CSIC), J. A. Martín Gago (ICMM-CSIC), J.Martín-Sánchez (IMM-CNM-CSIC), D. Martínez (UAM), J. Méndez (ICMM-CSIC), F. Moreno (CBM-CSIC), M. Moreno-Ugeda (UAM), S. Morita (Osaka University), C. Munuera (ICMAB-CSIC), C. Ocal(ICMAB-CSIC), E. Palacios-Lidón (University of Murcia), J. I. Pascual (Freie Universität Berlin), B.Pérez-García (Murcia Univ.), D. Porath (Hebrew University Jerusalem), E. Prieto (CEM), M. Puig(University of Barcelona), A. Raman (Purdue University), M. Reichling (Osnabrück University), R.Reifenberger (Purdue University), C. Rogero (INTA), A. San Paulo (IMB-CNM-CSIC), F. Sanz (Universityof Barcelona), I. Schaap (Vrije Universiteit Amsterdam), J. Soler (UAM), J. Sotres (ICMM-CSIC), Y. Sugimoto (Osaka University), P. Szabo (CLTP-SAS), F. Terán (Gaiker), J. L. Toca (CICbiomaGUNE) and all the people working in their groups.otherpartners32

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