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3.4. Ex situ characterization techniques 49 highly brilliant synchrotron light sources are available (e. g. PETRA III), the reduced photoemission cross-sections can be compensated by high-intensity hard X-ray radiation: photoemission spectra with a wide range of electron kinetic energies are thus available (example in Fig. 3.13). This, in turn, fulfills the key prerequisite for depth profiling of the electronic properties in multilayer structures including buried layers and interfaces, by analyzing photoelectrons of largely different kinetic energies. The HAXPES experiment at KMC1 beamline in the BESSY II storage ring Figure 3.14.: The HIKE endstation (a) is located at the KMC1 dipole magnet beamline (b) at the BESSY II storage ring in Berlin. Since 1994, the third generation synchrotron light source of the Helmholtz-Zentrum Berlin (Germany) provides access to a variety of experiments employing highly brillant X-ray light. Electrons are accelerated up to an energy of 1.7 GeV and are injected into the storage ring BESSY II. A variety of X-ray sources (undulator, wiggler and dipole magnet sources) with high energy resolution are in operation. The KMC-1 beamline disperses light from a dipole light source, and is coupled to the HIKE endstation with a SCIENTA R4000 electron spectrometer. Spectroscopy experiments can be conducted with a high energy resolution and an excitation energy up to 12 keV. A two-crystal Si monochromator provides mono-energetic light, achieving an overall energy resolution of 200 meV. Very high resolution is achieved around 2, 6 and 8 keV photon excitation energy due to an optimal Bragg reflection of the monochromator crystals. The instrumental resolution of the spectrometer can be better than 40 meV at 6 keV (Gorgoi et al. (2009)). 98 As depicted in Fig. 3.14a, the R4000 analyzer is positioned at an angle of 90 ◦ with respect to the incoming X-ray light. Thus, the excitation is at grazing incidence which lets the photo-
50 3. Experimental details electron emission be normal to the surface in the standard setup. This provides the largest escape depth of the photoelectrons and, moreover, lets the X-ray penetration depth match the electron escape depth, which minimizes the inelastic background of photoemission spectra. In this work, magnetic oxide on silicon heterostructures are investigated by high-resolution HAXPES measurements at the HIKE endstation. The HAXPES experiment at P09 beamline at PETRA III High heat load double crystal Si(111) and (311) monochromator High resolution secondary Si monochromator (under construction) Diamond phase retarder Hor./vert. pre-focusing mirrors KB mirrors (design phase) Sample PETRA III 6 GeV positron storage ring 46.5 m 48.5 m 50 m 53 m 93.5 m 94 m Figure 3.15.: Schematics of the beamline P09 at PETRA III. Courtesy Gloskovskii et al. (2012). 97 Since 2010, a very high photon brilliance due to its small emittance of 1 nmrad at 6 GeV makes X-ray light of the Positronen-Elektronen Tandembeschleunigeranlage (PETRA III storage ring) in Hamburg (Germany) perfectly suited for spectroscopic techniques requiring high energy resolution and high intensity. At the hard X-ray beamline P09 (Fig. 3.15), the energy adjustment of highly coherent light is provided by a two-meter undulator followed by a Si-crystal primary monochromator. For experiments requiring elliptically polarized light, a double-stage diamond phase retarder can be moved into the beam path in order to generate either linear or circularly polarized X-ray light. In order to allow for magnetization-dependent measurements of the magnetic circular dichroism effect , a permanent magnet can be approached by a non-magnetic ultrathinwalled feedthrough. In this way, we apply a large magnetic induction (B max 1 T) to the thin film sample, which remains then remanently magnetized. A high-resolution HAXPES setup using a SPECS Phoibos 225 HV delay line detector is installed as the spectroscopy endstation. The detector is situated along the dispersive direction of the spectrometer, which permits a detector resolution of 30 meV at 10 keV. 97 Figure 3.16 illustrates the arrangement of analysis chamber, the energy analyzer, and optionally magnetized thin film sample.
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Member of the Helmholtz Association
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Forschungszentrum Jülich GmbH Pete
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Zusammenfassung In dieser Doktorarb
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Contents 1. Introduction 1 2. Theor
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List of Figures 2.1. Phase diagram
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List of Figures xi 5.12. Resulting
Page 18 and 19: 1. Introduction Smart and powerful
Page 20 and 21: 3 In the thesis at ha
Page 22 and 23: 2. Theoretical background . . . The
Page 24 and 25: 2.1. The challenge of stabilizing s
Page 26 and 27: 2.2. Electronic structure of EuO 9
Page 28 and 29: 2.3. Magnetic properties of EuO 11
Page 36 and 37: 2.4. Hard X-ray photoemission spect
Page 46 and 47: 2.5. Magnetic circular dichroism in
Page 52 and 53: 3. Experimental details Die Pläne
Page 54 and 55: 3.1. Molecular beam epitaxy for oxi
Page 56 and 57: 3.2. In situ characterization techn
Page 58 and 59: 3.2. In situ characterization techn
Page 60 and 61: 3.3. Experimental developments at t
Page 62 and 63: 3.4. Ex situ characterization techn
Page 74 and 75: 4. Results I: Single-crystalline ep
Page 76 and 77: 59 Table 4.1.: Parameters for stoic
Page 78 and 79: 4.1. Coherent growth: EuO on YSZ (1
Page 92 and 93: 4.2. Lateral tensile strain: EuO on
Page 94 and 95: 4.2. Lateral tensile strain: EuO on
Page 96 and 97: 4.3. Lateral compressive strain: Eu
Page 102 and 103: 5. Results II: The integration of t
Page 104 and 105: 5.1. Chemical stabilization of bulk
Page 114 and 115: 5.2. Thermodynamic analysis of the
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5.2. Thermodynamic analysis of the
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5.3. Interface engineering I: Hydro
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5.4. Interface engineering II: Eu p
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5.5. Interface engineering III: SiO
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5.5. Interface engineering III: SiO
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5.6. Summary 121
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6. Conclusion and Outlook In the th
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125 Outlook and perspectives In the
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A.1. EuO-related phases and cubic o
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A.1. EuO-related phases and cubic o
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A.2. In situ analysis of the Si (00
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Bibliography 133 [13] S. S. P. Park
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Bibliography 135 [36] R. E. Dickers
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Bibliography 137 [65] R. Sutarto, S
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Bibliography 139 [91] P. Braun, M.
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Bibliography 141 [116] S. Hüfner.
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Bibliography 143 [144] R. Feder and
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Bibliography 145 [171] H. Miyazaki,
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Bibliography 147 [197] J. Qi, T. Ma
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Software and Internet Resources [21
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List of own publications 151 [10] R
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List of conference contributions 15
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Schriften des Forschungszentrums J
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Schlüsseltechnologien / Key Techno
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