{"id":{"repo_id":"njit","oai_identifier":"oai:digitalcommons.njit.edu:dissertations-1629"},"canonical_url":"https://search.dev.ndltd.org/etd/njit/oai:digitalcommons.njit.edu:dissertations-1629","repository":{"repo_id":"njit","name":"NJIT","base_url":"https://digitalcommons.njit.edu/do/oai/"},"display":{"title":"High pressure effects on electron transport and structure of colossal magnetoresistive materials","abstract":"Pressure effects on the electronic, magnetic properties and structure of several typical colossal magnetoresistive manganites, La_{0.60}Y_{0.07}Ca_{0.33}MnO_3, Pr_{1-x}Ca_xMn0_3 (X = 0.25, 0.30, 0.35), Nd_{1-x}Sr_xMnO_3 (x = 0.45, 0.50), were explored through high pressure resistivity and structure measurements. It was shown that pressure up to ~7 GPa induces more complicated charge, spin and lattice state changes than in the low pressure range explored previously. In La_{0.60}Y_{0.07}Ca_{0.33}MnO_3, pressure induces a local atomic structure transformation at a critical point P*, and hence, a non-monotonic change in metal insulator (MI) transition temperature (T_{mi}) and spin state. In Pr0.75Ca_{0.25}MnO_3, with pressure increase, T_{mi}, increases and T_c decreases below P* and the trend is reversed above P*. In Pr_{0.7}Ca_{0.3}MnO_3, pressure induces reentrant electronic and magnetic states: between ~0.8-5 GPa, T_{mI}, and T_c are coupled and have a behavior similar to La_{0.60}Y_{0.07}Ca_{0.33}MnO_3, outside of this range, T_{mI} and T_c are decoupled and at low and high pressure the material is insulating. In all three Pr_{1-x}Ca_xMnO_3 compounds, charge ordering is suppressed below P*. Above P*, an insulating state with unknown conducting mechanism is induced. In Nd_{1-x}Sr_xMnO_3, at x = 0.45, in addition to the effect on T_{mI}, pressure possibly induces an A-type antiferromagnetic phase. For x = 0.5, the charge ordering transition temperature is increased, which is different from Pr_{1-x}Ca_xMnO_3 system. The effects of chemical doping (bandwidth) and pressure are not equivalent in the high pressure range. This is unlike the results in the low pressure range acquired by other groups previously. A universal P* exists for samples with metal-insulator transitions.","abstract_html":"Pressure effects on the electronic, magnetic properties and structure of several typical colossal magnetoresistive manganites, La_{0.60}Y_{0.07}Ca_{0.33}MnO_3, Pr_{1-x}Ca_xMn0_3 (X = 0.25, 0.30, 0.35), Nd_{1-x}Sr_xMnO_3 (x = 0.45, 0.50), were explored through high pressure resistivity and structure measurements. It was shown that pressure up to ~7 GPa induces more complicated charge, spin and lattice state changes than in the low pressure range explored previously. In La_{0.60}Y_{0.07}Ca_{0.33}MnO_3, pressure induces a local atomic structure transformation at a critical point P*, and hence, a non-monotonic change in metal insulator (MI) transition temperature (T_{mi}) and spin state. In Pr0.75Ca_{0.25}MnO_3, with pressure increase, T_{mi}, increases and T_c decreases below P* and the trend is reversed above P*. In Pr_{0.7}Ca_{0.3}MnO_3, pressure induces reentrant electronic and magnetic states: between ~0.8-5 GPa, T_{mI}, and T_c are coupled and have a behavior similar to La_{0.60}Y_{0.07}Ca_{0.33}MnO_3, outside of this range, T_{mI} and T_c are decoupled and at low and high pressure the material is insulating. In all three Pr_{1-x}Ca_xMnO_3 compounds, charge ordering is suppressed below P*. Above P*, an insulating state with unknown conducting mechanism is induced. In Nd_{1-x}Sr_xMnO_3, at x = 0.45, in addition to the effect on T_{mI}, pressure possibly induces an A-type antiferromagnetic phase. For x = 0.5, the charge ordering transition temperature is increased, which is different from Pr_{1-x}Ca_xMnO_3 system. The effects of chemical doping (bandwidth) and pressure are not equivalent in the high pressure range. This is unlike the results in the low pressure range acquired by other groups previously. A universal P* exists for samples with metal-insulator transitions.","abstract_has_math":false,"creators":["Cui, Congwu"],"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","Gordon A. Thomas","Ken K. Chin"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2003,"date_issued":"2003-05-31T07:00:00Z","date_published":"2003-05-31T07:00:00Z","updated_at":"2026-07-24T03:22:52Z","subjects":["high pressure","manganite","coloccal magnetoresistance","correlated elctron system","structure","electron transport","Other Physics"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://digitalcommons.njit.edu/dissertations/574","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Trevor Tyson","Gordon A. Thomas","Ken K. Chin"]},{"key":"dc:creator","label":"Author","values":["Cui, Congwu"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:type","label":"Dc Type","values":["Dissertation"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Federated Physics Department"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy in Applied Physics - (Ph.D.)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["high pressure","manganite","coloccal magnetoresistance","correlated elctron system","structure","electron transport","Other Physics"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://digitalcommons.njit.edu/dissertations/574"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Pressure effects on the electronic, magnetic properties and structure of several typical colossal magnetoresistive manganites, La_{0.60}Y_{0.07}Ca_{0.33}MnO_3, Pr_{1-x}Ca_xMn0_3 (X = 0.25, 0.30, 0.35), Nd_{1-x}Sr_xMnO_3 (x = 0.45, 0.50), were explored through high pressure resistivity and structure measurements. It was shown that pressure up to ~7 GPa induces more complicated charge, spin and lattice state changes than in the low pressure range explored previously. In La_{0.60}Y_{0.07}Ca_{0.33}MnO_3, pressure induces a local atomic structure transformation at a critical point P*, and hence, a non-monotonic change in metal insulator (MI) transition temperature (T_{mi}) and spin state. In Pr0.75Ca_{0.25}MnO_3, with pressure increase, T_{mi}, increases and T_c decreases below P* and the trend is reversed above P*. In Pr_{0.7}Ca_{0.3}MnO_3, pressure induces reentrant electronic and magnetic states: between ~0.8-5 GPa, T_{mI}, and T_c are coupled and have a behavior similar to La_{0.60}Y_{0.07}Ca_{0.33}MnO_3, outside of this range, T_{mI} and T_c are decoupled and at low and high pressure the material is insulating. In all three Pr_{1-x}Ca_xMnO_3 compounds, charge ordering is suppressed below P*. Above P*, an insulating state with unknown conducting mechanism is induced. In Nd_{1-x}Sr_xMnO_3, at x = 0.45, in addition to the effect on T_{mI}, pressure possibly induces an A-type antiferromagnetic phase. For x = 0.5, the charge ordering transition temperature is increased, which is different from Pr_{1-x}Ca_xMnO_3 system. The effects of chemical doping (bandwidth) and pressure are not equivalent in the high pressure range. This is unlike the results in the low pressure range acquired by other groups previously. A universal P* exists for samples with metal-insulator transitions."]},{"key":"dc:title","label":"Title","values":["High pressure effects on electron transport and structure of colossal magnetoresistive materials"]}]}],"canonical_facts":{"dc:contributor":["Trevor Tyson","Gordon A. Thomas","Ken K. Chin"],"dc:creator":["Cui, Congwu"],"dc:description.abstract":["Pressure effects on the electronic, magnetic properties and structure of several typical colossal magnetoresistive manganites, La_{0.60}Y_{0.07}Ca_{0.33}MnO_3, Pr_{1-x}Ca_xMn0_3 (X = 0.25, 0.30, 0.35), Nd_{1-x}Sr_xMnO_3 (x = 0.45, 0.50), were explored through high pressure resistivity and structure measurements. It was shown that pressure up to ~7 GPa induces more complicated charge, spin and lattice state changes than in the low pressure range explored previously. In La_{0.60}Y_{0.07}Ca_{0.33}MnO_3, pressure induces a local atomic structure transformation at a critical point P*, and hence, a non-monotonic change in metal insulator (MI) transition temperature (T_{mi}) and spin state. In Pr0.75Ca_{0.25}MnO_3, with pressure increase, T_{mi}, increases and T_c decreases below P* and the trend is reversed above P*. In Pr_{0.7}Ca_{0.3}MnO_3, pressure induces reentrant electronic and magnetic states: between ~0.8-5 GPa, T_{mI}, and T_c are coupled and have a behavior similar to La_{0.60}Y_{0.07}Ca_{0.33}MnO_3, outside of this range, T_{mI} and T_c are decoupled and at low and high pressure the material is insulating. In all three Pr_{1-x}Ca_xMnO_3 compounds, charge ordering is suppressed below P*. Above P*, an insulating state with unknown conducting mechanism is induced. In Nd_{1-x}Sr_xMnO_3, at x = 0.45, in addition to the effect on T_{mI}, pressure possibly induces an A-type antiferromagnetic phase. For x = 0.5, the charge ordering transition temperature is increased, which is different from Pr_{1-x}Ca_xMnO_3 system. The effects of chemical doping (bandwidth) and pressure are not equivalent in the high pressure range. This is unlike the results in the low pressure range acquired by other groups previously. A universal P* exists for samples with metal-insulator transitions."],"dc:identifier":["https://digitalcommons.njit.edu/dissertations/574"],"dc:subject":["high pressure","manganite","coloccal magnetoresistance","correlated elctron system","structure","electron transport","Other Physics"],"dc:title":["High pressure effects on electron transport and structure of colossal magnetoresistive materials"],"dc:type":["Dissertation"],"thesis:degree_discipline":["Federated Physics Department"],"thesis:degree_name":["Doctor of Philosophy in Applied Physics - (Ph.D.)"]},"updated_at":"2026-07-24T03:22:52Z"}