PHYS07200604007 Manas Kumar Dala - Homi Bhabha National ...

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2.3 Inverse Photoemission Spectroscopy . . . . . . . . . . . . . . . . 38 2.3.1 Historical background . . . . . . . . . . . . . . . . . . . . . . 38 2.3.2 Basic principle . . . . . . . . . . . . . . . . . . . . . . . . . . 38 2.3.3 Basic interpretation of inverse photoemission . . . . . . . . . . 39 2.3.4 Experimental Set-up . . . . . . . . . . . . . . . . . . . . . . . 41 2.4 X-ray Absorption Spectroscopy . . . . . . . . . . . . . . . . . . . 45 2.4.1 Basic principle . . . . . . . . . . . . . . . . . . . . . . . . . . 45 2.4.2 Detection techniques . . . . . . . . . . . . . . . . . . . . . . . 47 2.5 Synchrotron Radiation . . . . . . . . . . . . . . . . . . . . . . . . 49 3 Electronic Structure of Pr 0.67 Ca 0.33 MnO 3 59 3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 3.2 Experimental . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 3.3 Results and Discussion . . . . . . . . . . . . . . . . . . . . . . . . 62 3.3.1 The UPS study of Pr 0.67 Ca 0.33 MnO 3 . . . . . . . . . . . . . . 62 3.3.2 The XAS study of Pr 0.67 Ca 0.33 MnO 3 . . . . . . . . . . . . . . 67 3.3.3 The Charge Transfer Energy (E CT ) . . . . . . . . . . . . . . . 69 3.4 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 4 Electronic Structure of Pr 1−x Ca x MnO 3 77 4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 4.2 Experimental . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 4.3 Results and Discussion . . . . . . . . . . . . . . . . . . . . . . . . 80 4.3.1 The UPS study of Pr 1−x Ca x MnO 3 , x = 0.2, 0.33 and 0.4 . . . 80 4.3.2 The IPES study of Pr 1−x Ca x MnO 3 , x = 0.2, 0.33, 0.4 and 1 . 84 4.3.3 The core levels of Pr 1−x Ca x MnO 3 , x = 0.2, 0.33, 0.4, and 0.84 87 4.4 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 5 Electronic Structure of Ca 0.86 Pr 0.14 MnO 3 96 5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 5.2 Experimental . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 5.3 Results and Discussion . . . . . . . . . . . . . . . . . . . . . . . . 98 5.4 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 6 Summary and Conclusions 108 xvi
List of Figures 1.1 Temperature dependence of the resistivity of La 1−x Sr x MnO 3 (x = 0.175) under various magnetic fields [2]. . . . . . . . . . . . . . . . . . 4 1.2 Schematic view of the cubic perovskite structure. . . . . . . . . . . . 5 1.3 Phase diagram of temperature versus tolerance factor for the system R 0.7 A 0.3 MnO 3 , where R is a trivalent rare earth ion and A is a divalent alkaline earth ion [12]. . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.4 A schematic of the electronic structure of Mn 3+ (a) and Mn 4+ (b). . . 7 1.5 Schematic features of the double exchange mechanism. . . . . . . . . 8 1.6 Schematic view of the Jahn-Teller effect for the d 4 ion. . . . . . . . . 9 1.7 Schematic representation of a macroscopic phase separated state (a), as well as possible charge inhomogeneous states stabilized by the longrange Coulomb interaction (spherical droplets in (b), stripes in (c)) [20]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 1.8 Different types of spin arrangements. . . . . . . . . . . . . . . . . . . 11 1.9 A Schematic picture of antiferromagnetic CE-type structure with the charge and e g orbital ordering. . . . . . . . . . . . . . . . . . . . . . . 12 1.10 A schematic picture of the antiferromagnetic pseudo-CE-type structure in the case of Pr 1−x Ca x MnO 3 (x = 0.4) [38]. . . . . . . . . . . . . . . 13 xvii
Page 1 and 2: SPECTROSCOPIC INVESTIGATIONS OF THE
Page 3 and 4: iii To My Parents
Page 5 and 6: Maharana, P. Khare, D. K. Basa, K.
Page 7 and 8: List of Publications/Preprints [1]
Page 9 and 10: Synopsis The perovskite type mangan
Page 11 and 12: to the t 2g and e g spin-up states
Page 13 and 14: Bibliography [1] R. von Helmolt, J.
Page 15: Contents CERTIFICATE Acknowledgemen
Page 19 and 20: 2.2 Schematic view of the energetic
Page 21 and 22: 3.4 O K edge x-ray absorption spect
Page 23 and 24: Chapter 1 Introduction 1
Page 25 and 26: Introduction 3 The temperature and
Page 27 and 28: Introduction 5 Figure 1.2: Schemati
Page 29 and 30: Introduction 7 Figure 1.4: A schema
Page 31 and 32: Introduction 9 Figure 1.6: Schemati
Page 33 and 34: Introduction 11 Figure 1.8: Differe
Page 35 and 36: Introduction 13 Figure 1.10: A sche
Page 37 and 38: Introduction 15 Figure 1.12: Schema
Page 39 and 40: Introduction 17 Figure 1.13: Phase
Page 41 and 42: Bibliography [1] R. von Helmolt, J.
Page 43 and 44: Introduction 21 [31] Damien Saurel,
Page 45 and 46: Chapter 2 Experimental Techniques 2
Page 47 and 48: Experimental Techniques 25 Figure 2
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Page 51 and 52: Experimental Techniques 29 and G(k,
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Page 57 and 58: Experimental Techniques 35 negative
Page 59 and 60: Experimental Techniques 37 ∆E = E
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Experimental Techniques 45 are weld
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Experimental Techniques 47 Figure 2
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Bibliography [1] H. Hertz, Ann. Phy
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Experimental Techniques 57 [35] K.
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Chapter 3 Electronic Structure of P
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Electronic Structure of Pr 0.67 Ca
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Bibliography [1] I. G. Deac, J. F.
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Chapter 4 Electronic Structure of P
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Electronic Structure of Pr 1−x Ca
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Electronic Structure of Ca 0.86 Pr
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Bibliography [1] C. Zener, Phys. Re
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Summary and Conclusions 109 In this
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