{"id":{"repo_id":"njit","oai_identifier":"oai:digitalcommons.njit.edu:dissertations-1562"},"canonical_url":"https://search.dev.ndltd.org/etd/njit/oai:digitalcommons.njit.edu:dissertations-1562","repository":{"repo_id":"njit","name":"NJIT","base_url":"https://digitalcommons.njit.edu/do/oai/"},"display":{"title":"Structural, transport and magnetic studies of perovskite Bi1-x Cax Mn O3","abstract":"This dissertation presents an investigation of the fundamental physics of the perovskite system Bi_{1-x}Ca_xMn0_3. This material belongs to a group of simple perovskites called the manganites which are of technological importance for magnetic device applications as read-head sensors. The Bi_{1-x}Ca_xMnO_3 system is known to exhibit charge ordering (and high sensitivity to magnetic fields) for a much broader range of x than the well-characterized La_{1-x}Ca_xMnO_3 system. However, the properties of Bi_{1-x}Ca_xMnO_3 over the entire doping range are not well understood. Magnetization and resistivity measurements (up to 30T) as well as x-ray absorption and x-ray diffraction measurements on Bi_{1-x}Ca_xMnO_3 were performed to correlate the structural, transport, and magnetic properties. The system was found to be insulating and antiferromagnetic for the entire range of x studied (x >= 0.4) except near x ~ 0.875 where glassy behavior was observed. Detailed magnetization measurements were performed as a function of field and temperature to explore the net moment on the Mn sites as a function of x. These measurements reveal the charge ordering and N6el temperatures. X-ray absorption measurements reveal significant structural distortions of the Mn-0 bond distributions with increasing Bi content that correlates directly with increasing charge-ordering temperatures. Moreover, x-ray diffraction data reveal peak splittings consistent with lower symmetry cells as the Bi content increases. These structural-magnetic correlations point to the importance of Mn0 distortions in stabilizing the charge-ordered state in the manganites. A structural, transport and magnetic phase diagram over the complete range of x has been developed.","abstract_html":"This dissertation presents an investigation of the fundamental physics of the perovskite system Bi_{1-x}Ca_xMn0_3. This material belongs to a group of simple perovskites called the manganites which are of technological importance for magnetic device applications as read-head sensors. The Bi_{1-x}Ca_xMnO_3 system is known to exhibit charge ordering (and high sensitivity to magnetic fields) for a much broader range of x than the well-characterized La_{1-x}Ca_xMnO_3 system. However, the properties of Bi_{1-x}Ca_xMnO_3 over the entire doping range are not well understood. Magnetization and resistivity measurements (up to 30T) as well as x-ray absorption and x-ray diffraction measurements on Bi_{1-x}Ca_xMnO_3 were performed to correlate the structural, transport, and magnetic properties. The system was found to be insulating and antiferromagnetic for the entire range of x studied (x >= 0.4) except near x ~ 0.875 where glassy behavior was observed. Detailed magnetization measurements were performed as a function of field and temperature to explore the net moment on the Mn sites as a function of x. These measurements reveal the charge ordering and N6el temperatures. X-ray absorption measurements reveal significant structural distortions of the Mn-0 bond distributions with increasing Bi content that correlates directly with increasing charge-ordering temperatures. Moreover, x-ray diffraction data reveal peak splittings consistent with lower symmetry cells as the Bi content increases. These structural-magnetic correlations point to the importance of Mn0 distortions in stabilizing the charge-ordered state in the manganites. A structural, transport and magnetic phase diagram over the complete range of x has been developed.","abstract_has_math":false,"creators":["Woo, Hyungje"],"institution":null,"degree_name":"Doctor of Philosophy in Applied Physics - (Ph.D.)","degree_level":null,"degree_discipline":"Federated Physics Department","degree_department":null,"school":null,"contributors":["Trevor Tyson","Mark C. Croft","S.-W. Cheong"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2001,"date_issued":"2001-08-31T07:00:00Z","date_published":"2001-08-31T07:00:00Z","updated_at":"2026-07-24T03:22:45Z","subjects":["perovskite system","manganites","read-head sensors","Other Physics"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://digitalcommons.njit.edu/dissertations/507","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Trevor Tyson","Mark C. Croft","S.-W. 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This material belongs to a group of simple perovskites called the manganites which are of technological importance for magnetic device applications as read-head sensors. The Bi_{1-x}Ca_xMnO_3 system is known to exhibit charge ordering (and high sensitivity to magnetic fields) for a much broader range of x than the well-characterized La_{1-x}Ca_xMnO_3 system. However, the properties of Bi_{1-x}Ca_xMnO_3 over the entire doping range are not well understood. Magnetization and resistivity measurements (up to 30T) as well as x-ray absorption and x-ray diffraction measurements on Bi_{1-x}Ca_xMnO_3 were performed to correlate the structural, transport, and magnetic properties. The system was found to be insulating and antiferromagnetic for the entire range of x studied (x >= 0.4) except near x ~ 0.875 where glassy behavior was observed. Detailed magnetization measurements were performed as a function of field and temperature to explore the net moment on the Mn sites as a function of x. These measurements reveal the charge ordering and N6el temperatures. X-ray absorption measurements reveal significant structural distortions of the Mn-0 bond distributions with increasing Bi content that correlates directly with increasing charge-ordering temperatures. Moreover, x-ray diffraction data reveal peak splittings consistent with lower symmetry cells as the Bi content increases. These structural-magnetic correlations point to the importance of Mn0 distortions in stabilizing the charge-ordered state in the manganites. A structural, transport and magnetic phase diagram over the complete range of x has been developed."]},{"key":"dc:title","label":"Title","values":["Structural, transport and magnetic studies of perovskite Bi1-x Cax Mn O3"]}]}],"canonical_facts":{"dc:contributor":["Trevor Tyson","Mark C. Croft","S.-W. Cheong"],"dc:creator":["Woo, Hyungje"],"dc:description.abstract":["This dissertation presents an investigation of the fundamental physics of the perovskite system Bi_{1-x}Ca_xMn0_3. This material belongs to a group of simple perovskites called the manganites which are of technological importance for magnetic device applications as read-head sensors. The Bi_{1-x}Ca_xMnO_3 system is known to exhibit charge ordering (and high sensitivity to magnetic fields) for a much broader range of x than the well-characterized La_{1-x}Ca_xMnO_3 system. However, the properties of Bi_{1-x}Ca_xMnO_3 over the entire doping range are not well understood. Magnetization and resistivity measurements (up to 30T) as well as x-ray absorption and x-ray diffraction measurements on Bi_{1-x}Ca_xMnO_3 were performed to correlate the structural, transport, and magnetic properties. The system was found to be insulating and antiferromagnetic for the entire range of x studied (x >= 0.4) except near x ~ 0.875 where glassy behavior was observed. Detailed magnetization measurements were performed as a function of field and temperature to explore the net moment on the Mn sites as a function of x. These measurements reveal the charge ordering and N6el temperatures. X-ray absorption measurements reveal significant structural distortions of the Mn-0 bond distributions with increasing Bi content that correlates directly with increasing charge-ordering temperatures. Moreover, x-ray diffraction data reveal peak splittings consistent with lower symmetry cells as the Bi content increases. These structural-magnetic correlations point to the importance of Mn0 distortions in stabilizing the charge-ordered state in the manganites. A structural, transport and magnetic phase diagram over the complete range of x has been developed."],"dc:identifier":["https://digitalcommons.njit.edu/dissertations/507"],"dc:subject":["perovskite system","manganites","read-head sensors","Other Physics"],"dc:title":["Structural, transport and magnetic studies of perovskite Bi1-x Cax Mn O3"],"dc:type":["Dissertation"],"thesis:degree_discipline":["Federated Physics Department"],"thesis:degree_name":["Doctor of Philosophy in Applied Physics - (Ph.D.)"]},"updated_at":"2026-07-24T03:22:45Z"}