Research Profile - Department of Materials Science and Metallurgy ...

Mark Blamire
Professor of Device Materials
MA University of Cambridge
PhD University of Cambridge
+44 (0) 1223 334359
mb52@cam.ac.uk
www.msm.cam.ac.uk/dmg/
Thin-Film Devices and Nanoscience
My research within the Device Materials Group is built around
the deposition, microfabrication and measurement of thin-film
heterostructure devices. In particular we apply novel materials
and advanced nanofabrication to create new types of functional
device.
Multifunctional heterostructure devices
Within a thin-film multilayer or heterostructure, ultra-thin layers
of materials with radically different properties (for example
superconductivity and magnetism) can be placed in contact so
that the interfacial coupling can begin to dominate the equilibrium
properties found in the bulk. If currents are passed through
such structures then the creation of non-equilibrium charge or
spin states is possible and so complex functional properties
can be created. Specific examples of this type of work includes
studies of spin accumulation in ferromagnetic heterostructures,
complex order parameter coupling in superconducting junctions
containing magnetic barriers, and the exchange coupling
between ferromagnets and antiferromagnets.
The best known of the metallic oxides are the high-temperature
superconductors, but materials with complex electronic
properties have similar crystal structures and can be grown
as thin films by laser ablation. Consequently, a major research
programme is the study of epitaxial oxide heterostructure devices
which enable tunnelling and direct injection of carriers between
materials with very different electronic properties.
Nanofabrication and materials modification
Within a heterostructure, thin-film deposition techniques enable
control of layer thickness to much better than 1 nanometre.
For many systems of interest, the confinement in the other
dimensions is much less critical, but there are several classes
of device for which high current densities need to be applied
through the layers and so methods of fabricating devices with
lateral dimensions of 100 nanometres or better need to be
developed.
We have developed focused-ion-beam nano-machining within
the Department as our primary technique for patterning. This
technique can be used not only for imaging device and materials
microstructures but also as a nanofabrication tool. As well as
direct device fabrication and measurement of device properties
while they are being patterned, we are developing highly localized
ion implantation for materials modification.
J Dho, X Qi, JL MacManus-Driscoll, MG Blamire & H Kim, “Large electric
polarisation and exchange bias in multiferroic BiFeO 3
” Adv. Mater. 18,
1445–1448 (2006).
JWA Robinson, S Piano, G Burnell, C Bell & MG Blamire, “Critical current
oscillations in strong ferromagnetic π-junctions" Phys. Rev. Lett. 97,
177003 (2006).
M.G Blamire, M Ali, CW Leung, CH Marrows & BJ Hickey, “Exchange bias
and blocking temperature in Co/FeMn/CuNi trilayers” Phys. Rev. Lett. 98,
217202 (2007).
A Palau, H Parvaneh, NA Stelmashenko, H Wang, JL Macmanus-Driscoll
& MG Blamire, “Hysteretic vortex pinning in superconductor / ferromagnet
nanocomposites” Phys. Rev. Lett. 98, 117003 (2007).
A device fabricated by 3-D focused ion beam milling used
to measure the spin diffusion length of electrons in copper
Research Profile 9