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The influence of cation doping on the electronic properties of Sr₃Ru₂O₇
Item metadata
dc.contributor.advisor | Mackenzie, Andrew | |
dc.contributor.author | Farrell, Jason | |
dc.coverage.spatial | 147 | en |
dc.date.accessioned | 2009-05-15T14:14:51Z | |
dc.date.available | 2009-05-15T14:14:51Z | |
dc.date.issued | 2008-11-27 | |
dc.identifier.uri | https://hdl.handle.net/10023/689 | |
dc.description.abstract | Sr₃Ru₂O₇ is a quasi-two-dimensional metal and has a paramagnetic ground state that is heavily renormalised by electron-electron correlations and magnetic exchange interactions. Inextricably linked to this renormalisation is the metamagnetism of Sr₃Ru₂O₇ - a rapid rise in uniform magnetisation over a narrow range of applied magnetic field. Knowledge of the zero-field physics is essential to any description of the metamagnetism. Light may be shed on the enigmatic ground state of Sr₃Ru₂O₇ by doping the crystal lattice with foreign cations: this is the primary purpose of the original research referred to in this thesis, in which studies of some of the electronic properties of crystals of cation-doped Sr₃Ru₂O₇ are reported. Single crystals of Sr₃(Ru[subscript(1-x)]Ti[subscript(x)])₂O₇ and Sr₃(Ru[subscript(1-x)]Cr[subscript(x)])₂O₇ have been synthesised in an image furnace and some of the properties of these crystals have been measured. Evidence that indicates the emergence of a spin density wave as a function of Ti-doping in Sr₃(Ru[subscript(1-x)]Ti[subscript(x)])₂O₇ is presented. Time-dependent magnetic irreversibility has been observed in samples of Sr₃(Ru[subscript(1-x)]Cr[subscript(x)])₂O₇, thus hinting at the involvement of the RKKY mechanism in these materials. Regarding cation doping out of the conducting RuO₂ planes, samples of (Sr[subscript(1-y)]La[subscript(y)])₃Ru₂O₇ have been grown and investigated. Both the Sommerfeld coefficient and the Fermi liquid A coefficient of (Sr[subscript(1-y)]La[subscript(y)])₃Ru₂O₇ are found to decrease as a function of y (0 ≤ y ≤ 0.02); these observations point towards a reduction in the thermodynamic mass of the Landau quasiparticles. Results from magnetoresistance and magnetisation measurements indicate that the metamagnetism of the (Sr[subscript(1-y)]La[subscript(y)])₃Ru₂O₇ series probably cannot be explained by a rigid band-shift model. Also, some aspects of these data imply that the metamagnetism cannot be fully accounted for by a spin fluctuation extension to the Ginzburg-Landau theory of uniform magnetisation. | en |
dc.format.extent | 8499767 bytes | |
dc.format.mimetype | application/pdf | |
dc.language.iso | en | en |
dc.publisher | University of St Andrews | |
dc.subject | Sr₃Ru₂O₇ | en |
dc.subject | Ruthenate | en |
dc.subject | Correlated electrons | en |
dc.subject | Magnetism | en |
dc.subject | Low temperature | en |
dc.subject | Cryogenics | en |
dc.subject | Crystal growth | en |
dc.subject | Floating zone | en |
dc.subject | Cation doping | en |
dc.subject | Metamagnetism | en |
dc.subject | Quantum criticality | en |
dc.subject | Perovskite | en |
dc.subject | Emergence | en |
dc.subject | Complexity | en |
dc.subject | Image furnace | en |
dc.subject | Fermi liquid | en |
dc.subject | Ginzburg Landau | en |
dc.subject | Stoner model | en |
dc.subject | Incongruent | en |
dc.subject | Adiabatic demagnetisation | en |
dc.subject | SQUID magnetometer | en |
dc.subject | Continuous flow cryostat | en |
dc.subject | Dilution refrigerator | en |
dc.subject | Heat capacity | en |
dc.subject | EDX | en |
dc.subject | Electron probe | en |
dc.title | The influence of cation doping on the electronic properties of Sr₃Ru₂O₇ | en |
dc.type | Thesis | en |
dc.contributor.sponsor | Engineering and Physical Sciences Research Council (EPSRC) | en |
dc.type.qualificationlevel | Doctoral | en |
dc.type.qualificationname | PhD Doctor of Philosophy | en |
dc.publisher.institution | The University of St Andrews | en |
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