000858704 001__ 858704
000858704 005__ 20210325084310.0
000858704 0247_ $$2Handle$$a2128/21067
000858704 0247_ $$2ISSN$$a1866-1807
000858704 020__ $$a978-3-95806-365-5
000858704 037__ $$aFZJ-2018-07549
000858704 041__ $$aEnglish
000858704 1001_ $$0P:(DE-Juel1)159565$$aFeng, Erxi$$b0$$eCorresponding author$$ufzj
000858704 245__ $$aMagnetic Order and Excitation in Frustrated Pyrochlore 5d - Transition Metal Oxides$$f- 2019-01-09
000858704 260__ $$aJülich$$bForschungszentrum Jülich GmbH Zentralbibliothek, Verlag$$c2018
000858704 300__ $$aIV, 182 S.
000858704 3367_ $$2DataCite$$aOutput Types/Dissertation
000858704 3367_ $$0PUB:(DE-HGF)3$$2PUB:(DE-HGF)$$aBook$$mbook
000858704 3367_ $$2ORCID$$aDISSERTATION
000858704 3367_ $$2BibTeX$$aPHDTHESIS
000858704 3367_ $$02$$2EndNote$$aThesis
000858704 3367_ $$0PUB:(DE-HGF)11$$2PUB:(DE-HGF)$$aDissertation / PhD Thesis$$bphd$$mphd$$s1546502260_1134
000858704 3367_ $$2DRIVER$$adoctoralThesis
000858704 4900_ $$aSchriften des Forschungszentrums Jülich. Reihe Schlüsseltechnologien / Key Technologies$$v187
000858704 502__ $$aRWTH Aachen, Diss., 2018$$bDr.$$cRWTH Aachen$$d2018
000858704 520__ $$aMotivated by the recent experimental realizations of novel magnetic phases and emergent quasiparticles, such as magnetic monopoles and Majorana fermions, in frustrated and topological quantum magnets, this thesis focuses on the studies of the magnetic ground state of a complete series of pyrochlore 5d transition metal oxides, including the Ln$_{2}$Ir$_{2}$O$_{7}$ (Ln =rare-earth elements) family and Nd$_{2}$Hf$_{2}$O$_{7}$, via in-house specific heat and magnetization measurements as well as advanced neutron scattering techniques. This has allowed us to establish a global phase diagram of the magnetic ground state of Ln$_{2}$Ir$_{2}$O$_{7}$. Except for Pr$_{2}$Ir$_{2}$O$_{7}$, other pyrochlore iridates exhibit a transition at finite temperature from a paramagnetic metal to an antiferromagnetic semimetal with the “all-in-all-out” magnetic order of the Ir$^{4+}$ sublattice. The magnetic ground-state of Ln$^{3+}$ is strongly dependent on the Ln$^{3+}$ single-ion anisotropy and the molecular magnetic field generated by the surrounding Ir$^{4+}$ sublattice. For the Ln$^{3+}$ ions with an easy-axis anisotropy along the local [1 1 1] axis, which is parallel to the molecular field, an “all-in-all-out” long-range magnetic order is universally observed on the Ln$^{3+}$ sublattice. On the contrary, for the Ln$^{3+}$ ions with an easy plane anisotropy, a dynamic spin liquid phase persists down to the sub-Kelvin temperature range. Furthermore, aided by the magnetic structure refinements, sum-rule analysis of the total magnetic moments, quantitative analyses of low-temperature magnetic entropy and simulations of inelastic neutron scattering spectra, a deeper understanding on the exotic magnetic order and emergent quantum excitations in the ground state of two representative 5d pyrochlore compounds, the metallic spin-ice Pr$_{2}$Ir$_{2}$O$_{7}$ and insulating quantum spin-ice candidate Nd$_{2}$Hf$_{2}$O$_{7}$, have been obtained. Pr$_{2}$Ir$_{2}$O$_{7}$ undergoes a magnetic transition from paramagnetic state to the “2-in-2-out” long-range order of Pr$^{3+}$ below 0.76 K, signalized by a slightly dispersive gapped magnetic excitation. Nd$_{2}$Hf$_{2}$O$_{7}$ shows an “all-in-all-out” longrange order of Nd$^{3+}$ below 0.53 K. Its magnetic excitation consists of a flat band modecentered at 0.1 meV and a dispersive mode up to 0.23 meV in the ordered state. The XYZ model based on the “dipole-octupole” ground-state doublet is introduced to explain these observations. The Occurrence of exotic quantum fragmentation of magnetic moments in Nd$_{2}$Hf$_{2}$O$_{7}$ can thus be confirmed.
000858704 536__ $$0G:(DE-HGF)POF3-524$$a524 - Controlling Collective States (POF3-524)$$cPOF3-524$$fPOF III$$x0
000858704 536__ $$0G:(DE-HGF)POF3-6212$$a6212 - Quantum Condensed Matter: Magnetism, Superconductivity (POF3-621)$$cPOF3-621$$fPOF III$$x1
000858704 536__ $$0G:(DE-HGF)POF3-6G15$$a6G15 - FRM II / MLZ (POF3-6G15)$$cPOF3-6G15$$fPOF III$$x2
000858704 536__ $$0G:(DE-HGF)POF3-6G4$$a6G4 - Jülich Centre for Neutron Research (JCNS) (POF3-623)$$cPOF3-623$$fPOF III$$x3
000858704 65027 $$0V:(DE-MLZ)SciArea-170$$2V:(DE-HGF)$$aMagnetism$$x0
000858704 65027 $$0V:(DE-MLZ)SciArea-240$$2V:(DE-HGF)$$aCrystallography$$x1
000858704 65027 $$0V:(DE-MLZ)SciArea-180$$2V:(DE-HGF)$$aMaterials Science$$x2
000858704 65017 $$0V:(DE-MLZ)GC-1604-2016$$2V:(DE-HGF)$$aMagnetic Materials$$x0
000858704 693__ $$0EXP:(DE-MLZ)DNS-20140101$$1EXP:(DE-MLZ)FRMII-20140101$$5EXP:(DE-MLZ)DNS-20140101$$6EXP:(DE-MLZ)NL6S-20140101$$aForschungs-Neutronenquelle Heinz Maier-Leibnitz$$eDNS: Diffuse scattering neutron time of flight spectrometer$$fNL6S$$x0
000858704 693__ $$0EXP:(DE-MLZ)SPODI-20140101$$1EXP:(DE-MLZ)FRMII-20140101$$5EXP:(DE-MLZ)SPODI-20140101$$6EXP:(DE-MLZ)SR8a-20140101$$aForschungs-Neutronenquelle Heinz Maier-Leibnitz$$eSPODI: High resolution powder diffractometer$$fSR8a$$x1
000858704 693__ $$0EXP:(DE-MLZ)TOF-TOF-20140101$$1EXP:(DE-MLZ)FRMII-20140101$$5EXP:(DE-MLZ)TOF-TOF-20140101$$6EXP:(DE-MLZ)NL2au-20140101$$aForschungs-Neutronenquelle Heinz Maier-Leibnitz$$eTOFTOF: Cold neutron time-of-flight spectrometer$$fNL2au$$x2
000858704 8564_ $$uhttps://juser.fz-juelich.de/record/858704/files/Schluesseltech_187.pdf$$yOpenAccess
000858704 909CO $$ooai:juser.fz-juelich.de:858704$$pdnbdelivery$$pVDB$$pVDB:MLZ$$pdriver$$popen_access$$popenaire
000858704 915__ $$0StatID:(DE-HGF)0510$$2StatID$$aOpenAccess
000858704 915__ $$0LIC:(DE-HGF)CCBY4$$2HGFVOC$$aCreative Commons Attribution CC BY 4.0
000858704 9141_ $$y2018
000858704 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)159565$$aForschungszentrum Jülich$$b0$$kFZJ
000858704 9131_ $$0G:(DE-HGF)POF3-524$$1G:(DE-HGF)POF3-520$$2G:(DE-HGF)POF3-500$$3G:(DE-HGF)POF3$$4G:(DE-HGF)POF$$aDE-HGF$$bKey Technologies$$lFuture Information Technology - Fundamentals, Novel Concepts and Energy Efficiency (FIT)$$vControlling Collective States$$x0
000858704 9131_ $$0G:(DE-HGF)POF3-621$$1G:(DE-HGF)POF3-620$$2G:(DE-HGF)POF3-600$$3G:(DE-HGF)POF3$$4G:(DE-HGF)POF$$9G:(DE-HGF)POF3-6212$$aDE-HGF$$bForschungsbereich Materie$$lVon Materie zu Materialien und Leben$$vIn-house research on the structure, dynamics and function of matter$$x1
000858704 9131_ $$0G:(DE-HGF)POF3-6G15$$1G:(DE-HGF)POF3-6G0$$2G:(DE-HGF)POF3-600$$3G:(DE-HGF)POF3$$4G:(DE-HGF)POF$$9G:(DE-HGF)POF3-6G15$$aDE-HGF$$bForschungsbereich Materie$$lGroßgeräte: Materie$$vFRM II / MLZ$$x2
000858704 9131_ $$0G:(DE-HGF)POF3-623$$1G:(DE-HGF)POF3-620$$2G:(DE-HGF)POF3-600$$3G:(DE-HGF)POF3$$4G:(DE-HGF)POF$$9G:(DE-HGF)POF3-6G4$$aDE-HGF$$bForschungsbereich Materie$$lVon Materie zu Materialien und Leben$$vFacility topic: Neutrons for Research on Condensed Matter$$x3
000858704 920__ $$lyes
000858704 9201_ $$0I:(DE-Juel1)JCNS-FRM-II-20110218$$kJCNS-FRM-II$$lJCNS-FRM-II$$x0
000858704 9201_ $$0I:(DE-Juel1)JCNS-2-20110106$$kJCNS-2$$lStreumethoden$$x1
000858704 980__ $$aphd
000858704 980__ $$aVDB
000858704 980__ $$aUNRESTRICTED
000858704 980__ $$abook
000858704 980__ $$aI:(DE-Juel1)JCNS-FRM-II-20110218
000858704 980__ $$aI:(DE-Juel1)JCNS-2-20110106
000858704 9801_ $$aFullTexts