Roman Atanasov, Marc du Plessis, Razvan Hirian, Rares Bortnic, Gabriela Souca, Iosif Grigore Deac
{"title":"多晶 Pr(0.65-x)GdxSr0.35MnO3 (x ≤ 0.3) 复合物的磁ocaloric 效应、磁传输和磁特性","authors":"Roman Atanasov, Marc du Plessis, Razvan Hirian, Rares Bortnic, Gabriela Souca, Iosif Grigore Deac","doi":"10.1016/j.jmmm.2024.172605","DOIUrl":null,"url":null,"abstract":"<div><div>Polycrystalline Pr<sub>0.65-x</sub>Gd<sub>x</sub>Sr<sub>0.35</sub>MnO<sub>3</sub> (x = 0.01, 0.05, 0.1, 0.2, 0.3) manganites were prepared by conventional solid-state method. Structural analysis has revealed a change in structure with x = 0.2, from Rhombohedral (<em>R-3c</em>) to Orthorhombic (<em>Pbnm</em>) symmetry. Small oxygen deficiency was found in the samples. The electrical measurements revealed typical colossal magnetoresistance (<em>CMR</em>) behavior, with single metal–insulator peak at <em>T<sub>p</sub></em> for all investigated samples. The small polaron hopping (<em>SPH</em>) and variable-range hopping (<em>VRH</em>) models were used to describe the electrical conduction above <em>T<sub>p</sub>.</em> Magnetic measurements show an increase in magnetization below the Curie temperature, <em>T</em><sub>C</sub>. Values of <em>T<sub>c</sub></em> diminish with increasing Gd<sup>3+</sup> content. Isothermal measurements around critical points suggest a possible interaction between the 4f-ions and Mn-sublattice The magnetic critical behavior analysis established the tri-critical mean-field model to be the governing model for the series. Large magnetic entropy change Δ<em>S</em><sub>M</sub> at near room temperature (278 K) was exhibited by the x = 0.01 sample at 2.2 J/kgK in μ<sub>0</sub>Δ<em>H</em> = 1 T and 5.36 J/kgK in μ<sub>0</sub>Δ<em>H</em> = 4 T. The largest <em>|</em>ΔS<sub>M</sub><em>|</em> value was shown by the x = 0.1 sample. The values of the relative cooling power (<em>RCP</em>) and the temperature-averaged entropy change (<em>TEC</em>) increased with substitution qualifying these compounds as magnetocaloric materials.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"611 ","pages":"Article 172605"},"PeriodicalIF":2.5000,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Magnetocaloric effect, magnetotransport and magnetic properties of polycrystalline Pr(0.65-x)GdxSr0.35MnO3 (x ≤ 0.3) compounds\",\"authors\":\"Roman Atanasov, Marc du Plessis, Razvan Hirian, Rares Bortnic, Gabriela Souca, Iosif Grigore Deac\",\"doi\":\"10.1016/j.jmmm.2024.172605\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Polycrystalline Pr<sub>0.65-x</sub>Gd<sub>x</sub>Sr<sub>0.35</sub>MnO<sub>3</sub> (x = 0.01, 0.05, 0.1, 0.2, 0.3) manganites were prepared by conventional solid-state method. Structural analysis has revealed a change in structure with x = 0.2, from Rhombohedral (<em>R-3c</em>) to Orthorhombic (<em>Pbnm</em>) symmetry. Small oxygen deficiency was found in the samples. The electrical measurements revealed typical colossal magnetoresistance (<em>CMR</em>) behavior, with single metal–insulator peak at <em>T<sub>p</sub></em> for all investigated samples. The small polaron hopping (<em>SPH</em>) and variable-range hopping (<em>VRH</em>) models were used to describe the electrical conduction above <em>T<sub>p</sub>.</em> Magnetic measurements show an increase in magnetization below the Curie temperature, <em>T</em><sub>C</sub>. Values of <em>T<sub>c</sub></em> diminish with increasing Gd<sup>3+</sup> content. Isothermal measurements around critical points suggest a possible interaction between the 4f-ions and Mn-sublattice The magnetic critical behavior analysis established the tri-critical mean-field model to be the governing model for the series. Large magnetic entropy change Δ<em>S</em><sub>M</sub> at near room temperature (278 K) was exhibited by the x = 0.01 sample at 2.2 J/kgK in μ<sub>0</sub>Δ<em>H</em> = 1 T and 5.36 J/kgK in μ<sub>0</sub>Δ<em>H</em> = 4 T. The largest <em>|</em>ΔS<sub>M</sub><em>|</em> value was shown by the x = 0.1 sample. The values of the relative cooling power (<em>RCP</em>) and the temperature-averaged entropy change (<em>TEC</em>) increased with substitution qualifying these compounds as magnetocaloric materials.</div></div>\",\"PeriodicalId\":366,\"journal\":{\"name\":\"Journal of Magnetism and Magnetic Materials\",\"volume\":\"611 \",\"pages\":\"Article 172605\"},\"PeriodicalIF\":2.5000,\"publicationDate\":\"2024-10-23\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Magnetism and Magnetic Materials\",\"FirstCategoryId\":\"88\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0304885324008965\",\"RegionNum\":3,\"RegionCategory\":\"材料科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"MATERIALS SCIENCE, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Magnetism and Magnetic Materials","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0304885324008965","RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}
Magnetocaloric effect, magnetotransport and magnetic properties of polycrystalline Pr(0.65-x)GdxSr0.35MnO3 (x ≤ 0.3) compounds
Polycrystalline Pr0.65-xGdxSr0.35MnO3 (x = 0.01, 0.05, 0.1, 0.2, 0.3) manganites were prepared by conventional solid-state method. Structural analysis has revealed a change in structure with x = 0.2, from Rhombohedral (R-3c) to Orthorhombic (Pbnm) symmetry. Small oxygen deficiency was found in the samples. The electrical measurements revealed typical colossal magnetoresistance (CMR) behavior, with single metal–insulator peak at Tp for all investigated samples. The small polaron hopping (SPH) and variable-range hopping (VRH) models were used to describe the electrical conduction above Tp. Magnetic measurements show an increase in magnetization below the Curie temperature, TC. Values of Tc diminish with increasing Gd3+ content. Isothermal measurements around critical points suggest a possible interaction between the 4f-ions and Mn-sublattice The magnetic critical behavior analysis established the tri-critical mean-field model to be the governing model for the series. Large magnetic entropy change ΔSM at near room temperature (278 K) was exhibited by the x = 0.01 sample at 2.2 J/kgK in μ0ΔH = 1 T and 5.36 J/kgK in μ0ΔH = 4 T. The largest |ΔSM| value was shown by the x = 0.1 sample. The values of the relative cooling power (RCP) and the temperature-averaged entropy change (TEC) increased with substitution qualifying these compounds as magnetocaloric materials.
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The Journal of Magnetism and Magnetic Materials provides an important forum for the disclosure and discussion of original contributions covering the whole spectrum of topics, from basic magnetism to the technology and applications of magnetic materials. The journal encourages greater interaction between the basic and applied sub-disciplines of magnetism with comprehensive review articles, in addition to full-length contributions. In addition, other categories of contributions are welcome, including Critical Focused issues, Current Perspectives and Outreach to the General Public.
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