Ferromagnetic (Ga,Mn)As Layers and ... - OPUS Würzburg

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84 5. Local Anisotropy Control by Strain Engineering
Chapter 6 Device Application As stated in the beginning, the ultimate goal of this work was to establish a wellunderstood foundation for the design of a class of novel devices which make use of multiple connected regions with individually engineered anisotropy properties. In this chapter, we present investigations on the first such device as published by K. Pappert et. al. [Papp 07d]. Figure 6.1: SEM image of the L-shaped structure consisting of two connected (Ga,Mn)As nanobars. The bright stripes leading to the image edges are Ti/Au current and voltage leads. The definition for the writing angle ϕ as well as current and voltage are indicated. The device is shown in Fig. 6.1 and consists of two (Ga,Mn)As nanobars which are oriented perpendicular to each other and connected at one of the edges via a constriction. The resistance of an electrical current driven through this constriction depends on the relative magnetization states of the nanobars and is determined by the AMR effect. 85
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Ferromagnetic (Ga,Mn)As Layers and
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Contents Zusammenfassung 5 Summary
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Zusammenfassung Ferromagnetische Ha
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Anisotropiekontrolle in (Ga,Mn)As i
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Summary The great promise of ferrom
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Chapter 1 Introduction The event co
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13 investigated with SQUID and magn
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Chapter 2 The (Ga,Mn)As Material Sy
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2.1. Ferromagnetism in (Ga,Mn)As 17
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2.2. Band Structure Calculations in
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2.3. Magnetic Anisotropy 21 growth
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2.3. Magnetic Anisotropy 23 E n e r
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2.3. Magnetic Anisotropy 25 Figure
Page 27 and 28:
Chapter 3 MBE Growth of Ferromagnet
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3.2. Epitaxial Growth of (Ga,Mn)As
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3.3. Crystal Defects 31 lead to a d
Page 33 and 34: 3.4. RHEED 33 Figure 3.5: (a) Ewald
Page 35 and 36: 3.5. X-Ray Diffraction 35 1 0 7 1 0
Page 37 and 38: 3.5. X-Ray Diffraction 37 between t
Page 39 and 40: 3.5. X-Ray Diffraction 39 lattice d
Page 41 and 42: 3.5. X-Ray Diffraction 41 substrate
Page 43 and 44: Chapter 4 Finite Element Simulation
Page 45 and 46: 4.1. Derivation of the Equation Sys
Page 47 and 48: 4.2. The FlexPDE Software 47 4.2 Th
Page 49 and 50: 4.3. Simulation Results - Physical
Page 55 and 56: 4.4. Simulation Results - (In,Ga)As
Page 57 and 58: 4.5. Stripes Along [1¯10] 57 Figur
Page 59 and 60: 4.5. Stripes Along [1¯10] 59 in-pl
Page 61 and 62: Chapter 5 Local Anisotropy Control
Page 63 and 64: 5.1. Patterning and Structural Char
Page 73 and 74: 5.2. Magnetic Characterization 73 p
Page 75 and 76: 5.2. Magnetic Characterization 75 1
Page 77 and 78: 5.2. Magnetic Characterization 77 8
Page 79 and 80: 5.3. Shape Anisotropy 79 ∼ 0.2 k
Page 81 and 82: 5.4. A Model for Anisotropy Orienta
Page 83: 5.4. A Model for Anisotropy Orienta
Page 87 and 88: 6.2. The Role of the Constriction 8
Page 93 and 94: Chapter 7 Conclusion and Outlook Th
Page 95 and 96: Appendix A Band Structure Hamiltoni
Page 97 and 98: Appendix B Sample FlexPDE Input Fil
Page 99 and 100: 99 BOUNDARIES s u r f a c e ’ s u
Page 101 and 102: Bibliography [Abol 01] M. Abolfath,
Page 103 and 104: 103 [McGu 75] T. R. McGuire and R.
Page 105 and 106: Publications • J. Wenisch, C. Gou
Page 107: Acknowledgements There is a number
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