Ln[subscript]2CuO[subscript]4 (Ln = La, Pr, Nd, Sm, Eu, Gd) undergo structural transitions to oxygen-reduced structures Ln[subscript]2CuO[subscript]4-d with Ln = La, d = 1/3 and Ln = Pr, Nd, Sm, Eu, Gd, d = 1/2. The Nd[subscript]2CuO[subscript]4-type (T[superscript]'-phase) La[subscript]2CuO[subscript]4+d is observed after reoxygenation of oxygen-reduced La[subscript]2CuO[subscript]3.67 structure below 500°C. The magnetic properties of T/O (K[subscript]2NiF[subscript]4-type structure)-phase La[subscript]2CuO[subscript]4 systems show quite different behaviors compared with those of conventional solid state reacted La[subscript]2CuO[subscript]4 systems. The implications of these nonsuperconducting behaviors within the superconducting carrier concentrations are discussed from the structural point of view;La[subscript]2-xM[subscript]xCuO[subscript]4+d (M = Ca, Sr; x = 0.05, 0.15), synthesized by the low temperature route, also contain excess oxygen and show different physical properties. [superscript]139La NQR measurements of nonsuperconducting La[subscript]1.85Sr[subscript]0.15CuO[subscript]4.04 show metallic properties. The tolerance factor, which is based on ionic radii, is quite successful to describe structural properties of K[subscript]2NiF[subscript]4 related cuprate compounds. With anisotropic thermal motions of apical oxygens in La[subscript]2CuO[subscript]4, we discuss the crucial role of out-of-plane oxygens for stabilization of cuprate structures;The magnetic phase diagram and phase separation of La[subscript]2-xSr[subscript]xCuO[subscript]4+[delta] system (0.000≤ x≤ 0.030, 0.0≤[delta]) are reported. From the decrease of T[subscript]c by doping level, we infer the localization and pair-breaking mechanism induced by doped holes. Phase separation is realized within the appearance of three-dimensional antiferromagnetic order. We also observe scaling properties of susceptibilities versus renormalized temperatures and infer the finite size effects by doped holes from the scaling;[superscript]139La NQR spin-lattice relaxation rates vs temperature are presented for La[subscript]2-xSr[subscript]xCuO[subscript]4 with x = 0.02 to 0.08. The spin-lattice relaxation rate below ~2T[subscript]N(x) shows a power-law critical behavior while above ~2T[subscript]N(x) it follows an exponential law with a small x-dependent spin-stiffness constant, where T[subscript]N is the magnetic ordering temperature. It is argued that the spin-lattice relaxation rate arises from fluctuations of the staggered magnetization in locally ordered mesoscopic domains. We infer that the magnetically ordered state is not a conventional spin glass.
","abstract_html":"<p>Ln[subscript]2CuO[subscript]4 (Ln = La, Pr, Nd, Sm, Eu, Gd) undergo structural transitions to oxygen-reduced structures Ln[subscript]2CuO[subscript]4-d with Ln = La, d = 1/3 and Ln = Pr, Nd, Sm, Eu, Gd, d = 1/2. The Nd[subscript]2CuO[subscript]4-type (T[superscript]'-phase) La[subscript]2CuO[subscript]4+d is observed after reoxygenation of oxygen-reduced La[subscript]2CuO[subscript]3.67 structure below 500°C. The magnetic properties of T/O (K[subscript]2NiF[subscript]4-type structure)-phase La[subscript]2CuO[subscript]4 systems show quite different behaviors compared with those of conventional solid state reacted La[subscript]2CuO[subscript]4 systems. The implications of these nonsuperconducting behaviors within the superconducting carrier concentrations are discussed from the structural point of view;La[subscript]2-xM[subscript]xCuO[subscript]4+d (M = Ca, Sr; x = 0.05, 0.15), synthesized by the low temperature route, also contain excess oxygen and show different physical properties. [superscript]139La NQR measurements of nonsuperconducting La[subscript]1.85Sr[subscript]0.15CuO[subscript]4.04 show metallic properties. The tolerance factor, which is based on ionic radii, is quite successful to describe structural properties of K[subscript]2NiF[subscript]4 related cuprate compounds. With anisotropic thermal motions of apical oxygens in La[subscript]2CuO[subscript]4, we discuss the crucial role of out-of-plane oxygens for stabilization of cuprate structures;The magnetic phase diagram and phase separation of La[subscript]2-xSr[subscript]xCuO[subscript]4+[delta] system (0.000≤ x≤ 0.030, 0.0≤[delta]) are reported. From the decrease of T[subscript]c by doping level, we infer the localization and pair-breaking mechanism induced by doped holes. Phase separation is realized within the appearance of three-dimensional antiferromagnetic order. We also observe scaling properties of susceptibilities versus renormalized temperatures and infer the finite size effects by doped holes from the scaling;[superscript]139La NQR spin-lattice relaxation rates vs temperature are presented for La[subscript]2-xSr[subscript]xCuO[subscript]4 with x = 0.02 to 0.08. The spin-lattice relaxation rate below ~2T[subscript]N(x) shows a power-law critical behavior while above ~2T[subscript]N(x) it follows an exponential law with a small x-dependent spin-stiffness constant, where T[subscript]N is the magnetic ordering temperature. It is argued that the spin-lattice relaxation rate arises from fluctuations of the staggered magnetization in locally ordered mesoscopic domains. We infer that the magnetically ordered state is not a conventional spin glass.</p>","abstract_has_math":false,"creators":["Cho, Jin Hyung"],"institution":null,"degree_name":"Doctor of Philosophy","degree_level":"dissertation","degree_discipline":null,"degree_department":"Department of Physics and Astronomy","school":null,"contributors":[],"advisors":["D. C. Johnston"],"committee_chairs":[],"committee_members":[],"year":1992,"date_issued":"1992","date_published":"1992","updated_at":"2026-07-24T02:37:38Z","subjects":[],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier.doi","label":"DOI","values":["https://doi.org/10.31274/rtd-180813-11339"],"render_values":[{"text":"https://doi.org/10.31274/rtd-180813-11339","href":"https://doi.org/10.31274/rtd-180813-11339","code":true}]},{"key":"dc:identifier","label":"Identifier","values":["archive/lib.dr.iastate.edu/rtd/9824/"],"render_values":[{"text":"archive/lib.dr.iastate.edu/rtd/9824/","href":null,"code":true}]}]},"links":{"outbound_url":"https://dr.lib.iastate.edu/handle/20.500.12876/82965","outbound_label":"Repository record","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["D. C. Johnston"]},{"key":"dc:contributor.department","label":"Department","values":["Department of Physics and Astronomy"]},{"key":"dc:creator","label":"Author","values":["Cho, Jin Hyung"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2018-08-15T06:17:16.000"]},{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2020-07-02T06:15:53Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2020-07-02T06:15:53Z"]},{"key":"dc:date.issued","label":"Date","values":["1992"]},{"key":"dc:type","label":"Dc Type","values":["dissertation"]},{"key":"thesis:degree_level","label":"Degree Level","values":["dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["archive/lib.dr.iastate.edu/rtd/9824/"]},{"key":"dc:identifier.doi","label":"DOI","values":["https://doi.org/10.31274/rtd-180813-11339"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://dr.lib.iastate.edu/handle/20.500.12876/82965"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Ln[subscript]2CuO[subscript]4 (Ln = La, Pr, Nd, Sm, Eu, Gd) undergo structural transitions to oxygen-reduced structures Ln[subscript]2CuO[subscript]4-d with Ln = La, d = 1/3 and Ln = Pr, Nd, Sm, Eu, Gd, d = 1/2. The Nd[subscript]2CuO[subscript]4-type (T[superscript]'-phase) La[subscript]2CuO[subscript]4+d is observed after reoxygenation of oxygen-reduced La[subscript]2CuO[subscript]3.67 structure below 500°C. The magnetic properties of T/O (K[subscript]2NiF[subscript]4-type structure)-phase La[subscript]2CuO[subscript]4 systems show quite different behaviors compared with those of conventional solid state reacted La[subscript]2CuO[subscript]4 systems. The implications of these nonsuperconducting behaviors within the superconducting carrier concentrations are discussed from the structural point of view;La[subscript]2-xM[subscript]xCuO[subscript]4+d (M = Ca, Sr; x = 0.05, 0.15), synthesized by the low temperature route, also contain excess oxygen and show different physical properties. [superscript]139La NQR measurements of nonsuperconducting La[subscript]1.85Sr[subscript]0.15CuO[subscript]4.04 show metallic properties. The tolerance factor, which is based on ionic radii, is quite successful to describe structural properties of K[subscript]2NiF[subscript]4 related cuprate compounds. With anisotropic thermal motions of apical oxygens in La[subscript]2CuO[subscript]4, we discuss the crucial role of out-of-plane oxygens for stabilization of cuprate structures;The magnetic phase diagram and phase separation of La[subscript]2-xSr[subscript]xCuO[subscript]4+[delta] system (0.000≤ x≤ 0.030, 0.0≤[delta]) are reported. From the decrease of T[subscript]c by doping level, we infer the localization and pair-breaking mechanism induced by doped holes. Phase separation is realized within the appearance of three-dimensional antiferromagnetic order. We also observe scaling properties of susceptibilities versus renormalized temperatures and infer the finite size effects by doped holes from the scaling;[superscript]139La NQR spin-lattice relaxation rates vs temperature are presented for La[subscript]2-xSr[subscript]xCuO[subscript]4 with x = 0.02 to 0.08. The spin-lattice relaxation rate below ~2T[subscript]N(x) shows a power-law critical behavior while above ~2T[subscript]N(x) it follows an exponential law with a small x-dependent spin-stiffness constant, where T[subscript]N is the magnetic ordering temperature. It is argued that the spin-lattice relaxation rate arises from fluctuations of the staggered magnetization in locally ordered mesoscopic domains. We infer that the magnetically ordered state is not a conventional spin glass.
"]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Synthesis and magnetic properties of novel Ln[subscript 2-x]MxCuO[subscript 4+y] compositions (Ln = La,Pr,Nd,Sm,Eu,Gd; M = Ca,Sr,Ba; 0<=x<=0.2; -0.5<=y<=0.5)"]}]}],"canonical_facts":{"dc:contributor.advisor":["D. C. Johnston"],"dc:contributor.department":["Department of Physics and Astronomy"],"dc:creator":["Cho, Jin Hyung"],"dc:date":["2018-08-15T06:17:16.000"],"dc:date.accessioned":["2020-07-02T06:15:53Z"],"dc:date.available":["2020-07-02T06:15:53Z"],"dc:date.issued":["1992"],"dc:description.abstract":["Ln[subscript]2CuO[subscript]4 (Ln = La, Pr, Nd, Sm, Eu, Gd) undergo structural transitions to oxygen-reduced structures Ln[subscript]2CuO[subscript]4-d with Ln = La, d = 1/3 and Ln = Pr, Nd, Sm, Eu, Gd, d = 1/2. The Nd[subscript]2CuO[subscript]4-type (T[superscript]'-phase) La[subscript]2CuO[subscript]4+d is observed after reoxygenation of oxygen-reduced La[subscript]2CuO[subscript]3.67 structure below 500°C. The magnetic properties of T/O (K[subscript]2NiF[subscript]4-type structure)-phase La[subscript]2CuO[subscript]4 systems show quite different behaviors compared with those of conventional solid state reacted La[subscript]2CuO[subscript]4 systems. The implications of these nonsuperconducting behaviors within the superconducting carrier concentrations are discussed from the structural point of view;La[subscript]2-xM[subscript]xCuO[subscript]4+d (M = Ca, Sr; x = 0.05, 0.15), synthesized by the low temperature route, also contain excess oxygen and show different physical properties. [superscript]139La NQR measurements of nonsuperconducting La[subscript]1.85Sr[subscript]0.15CuO[subscript]4.04 show metallic properties. The tolerance factor, which is based on ionic radii, is quite successful to describe structural properties of K[subscript]2NiF[subscript]4 related cuprate compounds. With anisotropic thermal motions of apical oxygens in La[subscript]2CuO[subscript]4, we discuss the crucial role of out-of-plane oxygens for stabilization of cuprate structures;The magnetic phase diagram and phase separation of La[subscript]2-xSr[subscript]xCuO[subscript]4+[delta] system (0.000≤ x≤ 0.030, 0.0≤[delta]) are reported. From the decrease of T[subscript]c by doping level, we infer the localization and pair-breaking mechanism induced by doped holes. Phase separation is realized within the appearance of three-dimensional antiferromagnetic order. We also observe scaling properties of susceptibilities versus renormalized temperatures and infer the finite size effects by doped holes from the scaling;[superscript]139La NQR spin-lattice relaxation rates vs temperature are presented for La[subscript]2-xSr[subscript]xCuO[subscript]4 with x = 0.02 to 0.08. The spin-lattice relaxation rate below ~2T[subscript]N(x) shows a power-law critical behavior while above ~2T[subscript]N(x) it follows an exponential law with a small x-dependent spin-stiffness constant, where T[subscript]N is the magnetic ordering temperature. It is argued that the spin-lattice relaxation rate arises from fluctuations of the staggered magnetization in locally ordered mesoscopic domains. We infer that the magnetically ordered state is not a conventional spin glass.
"],"dc:format.mimetype":["application/pdf"],"dc:identifier":["archive/lib.dr.iastate.edu/rtd/9824/"],"dc:identifier.doi":["https://doi.org/10.31274/rtd-180813-11339"],"dc:identifier.uri":["https://dr.lib.iastate.edu/handle/20.500.12876/82965"],"dc:language.iso":["en"],"dc:title":["Synthesis and magnetic properties of novel Ln[subscript 2-x]MxCuO[subscript 4+y] compositions (Ln = La,Pr,Nd,Sm,Eu,Gd; M = Ca,Sr,Ba; 0<=x<=0.2; -0.5<=y<=0.5)"],"dc:type":["dissertation"],"thesis:degree_level":["dissertation"],"thesis:degree_name":["Doctor of Philosophy"]},"updated_at":"2026-07-24T02:37:38Z"}