Magnetotransport and magnetocaloric effects in intermetallic compounds

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Duijn, H.G.M.

Publication date

2000

Link to publication

Citation for published version (APA):

Duijn, H. G. M. (2000). Magnetotransport and magnetocaloric effects in intermetallic

compounds.

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Contents s

Introductionn 7

1.11 General introduction 7 1.22 Outline 9

22 Theoretical aspects 11

2.11 Magnetism in metals 11 2.1.11 Local-moment versus itinerant-electron magnetism 11

2.1.22 Phase transitions in itinerant-electron systems 14

2.22 Electrical resistance in metals 17

2.2.11 Basic concepts 17 2.2.22 Band-structure effects and spin-dependent scattering 20

2.2.33 Magnetic scattering 23 2.33 Theory of group representations 27

33 Experimental 35

3.11 Sample preparation 35 3.22 Characterisation techniques 36 3.33 Electrical-resistivity measurements 37

3.44 Magnetic measurements 38 3.55 Measurements under hydrostatic pressure 41

3.66 Neutron-diffraction experiments 41

44 Magnetic and transport properties of (Hf,Ta)Fe

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compounds 47

4.11 Introduction 47 4.22 Sample preparation and characterisation 49

4.33 Structural properties 50 4.44 Magnetic properties 51 4.55 Powder neutron diffraction 61 4.66 Application of the theory of group representations 64

4.77 Single-crystal neutron diffraction 66

4.88 Electrical resistivity 69

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55 Magnetic and transport properties of Fe

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(Ga^l)

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compounds 85

5.11 Introduction 85 5.22 Sample preparation and characterisation 86

5.33 Structural properties 87 5.44 Magnetic properties 89 5.55 Pressure dependence of the ferromagnetic to antiferromagnetic transition 94

5.66 Powder neutron diffraction 96

5.77 Specific heat 97 5.88 Electrical resistivity 99 5.99 Discussion 105

66 Electrical-transport properties of GdT

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Si2 compounds 109

6.11 Introduction 109 6.22 Experimental 111 6.33 Results and discussion 111

6.44 Conclusions 130

77 Electrical-transport properties of RMn

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Ge6 compounds 133

7.11 Introduction 133 7.22 Magnetic properties 134

7.33 Results 136 7.44 Discussion 141

88 Magnetic properties of Gd

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(Ge,Si)

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compounds 145

8.11 Introduction 145 8.22 Experimental 146 8.33 Structural properties 148 8.44 Application of the theory of group representations 151

8.55 Magnetic properties 152 8.66 Electrical resistance 160 8.77 Discussion 163 Appendixx A 169 Appendixx B 176 Summaryy 179 Samenvattingg 182 Listt of publications 185 Dankwoord d 186 6

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