Inelastic neutron scattering studies of magnetic fluctuations in the tetragonal and collapsed tetragonal phases of CaFe<sub>2</sub>As<sub>2</sub>

dc.contributor.advisor Alan I. Goldman
dc.contributor.author Soh, Jing Han
dc.contributor.department Department of Physics and Astronomy
dc.date 2018-08-11T15:19:30.000
dc.date.accessioned 2020-06-30T02:50:48Z
dc.date.available 2020-06-30T02:50:48Z
dc.date.copyright Tue Jan 01 00:00:00 UTC 2013
dc.date.embargo 2015-07-30
dc.date.issued 2013-01-01
dc.description.abstract <p>The relationship between magnetism and superconductivity has become a central topic of research in studies of superconductivity in the iron pnictides. This thesis presents inelastic neutron scattering studies of the magnetic excitations in FeAs flux-grown CaFe<sub>2</sub>As<sub>2</sub>. The ex- perimental data collected using ARCS time-of-flight chopper spectrometer have been analyzed and compared with theoretical models. The focus here is on the role played by antiferromag- netic (AFM) spin fluctuations in superconductivity. We present unambiguous evidence of the absence of magnetic fluctuations in the non-superconducting volume collapsed tetragonal (cT) phase of CaFe<sub>2</sub>As<sub>2</sub> via inelastic neutron scattering time-of-flight data, which is consistent with the view that spin fluctuations are a necessary ingredient for unconventional superconductivity in the iron pnictides. We demonstrate that the cT phase of CaFe<sub>2</sub>As<sub>2</sub> is non-magnetic, raising new questions regarding recent reports of high-temperature superconductivity in the cT phase of closely related compounds.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/etd/13593/
dc.identifier.articleid 4600
dc.identifier.contextkey 5050434
dc.identifier.doi https://doi.org/10.31274/etd-180810-3321
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath etd/13593
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/27780
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/etd/13593/Soh_iastate_0097M_13971.pdf|||Fri Jan 14 19:56:11 UTC 2022
dc.subject.disciplines Condensed Matter Physics
dc.subject.disciplines Physics
dc.subject.keywords 122
dc.subject.keywords iron-arsenide
dc.subject.keywords neutron scattering
dc.subject.keywords single-crystal
dc.subject.keywords superconductor
dc.subject.keywords time-of-flight
dc.title Inelastic neutron scattering studies of magnetic fluctuations in the tetragonal and collapsed tetragonal phases of CaFe<sub>2</sub>As<sub>2</sub>
dc.type thesis
dc.type.genre thesis
dspace.entity.type Publication
relation.isOrgUnitOfPublication 4a05cd4d-8749-4cff-96b1-32eca381d930
thesis.degree.level thesis
thesis.degree.name Master of Science
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