Crossover of the magnetocaloric effect and its importance on the determination of the critical behaviour in the La<subscript>0.67</subscript>Ba<subscript>0.33</subscript>Mn<subscript>0.9</subscript>Cr<subscript>0.1</subscript>O<subscript>3</subscript> perovskite manganite
In: Journal of Alloys & Compounds, Jg. 539 (2012-10-25), S. 116-123
Online
academicJournal
Zugriff:
Abstract: The magnetic phase transition and the magnetic entropy change (−ΔSM ) in the La0.67Ba0.33Mn0.9Cr0,1O3 manganite were investigated by measuring the magnetization as a function of temperature. The maximum magnetic entropy change (−ΔSM ) and the relative cooling power (RCP) are found to be, respectively, 4.20Jkg−1 K−1 and 238Jkg−1 for a 5-T field change, making of this material a promising candidate for magnetic refrigeration near room temperature. To investigate the nature of the paramagnetic (PM) to ferromagnetic (FM) phase transition, found to be of second-order, we performed a critical exponents study by dc-magnetization M(H,T) measurements around the Curie temperature T C, in a temperature range including the critical region |ɛ|=|T − T C|/T C ⩽0.05. From the derived values of the critical exponents (β =0.380, γ =1.345), we conclude that La0.67Ba0.33Mn0.9Cr0.1O3 belongs to the three-dimensional Heisenberg class with short-range interaction. Scaling relations are obeyed, indicating renormalized interactions around T C. By investigating the field dependence of RCP and ΔSM , it was possible to evaluate the critical exponents of the magnetic phase transitions. Their values are in good agreement with those obtained from the critical exponents using a modified Arrott method. [Copyright &y& Elsevier]
Titel: |
Crossover of the magnetocaloric effect and its importance on the determination of the critical behaviour in the La<subscript>0.67</subscript>Ba<subscript>0.33</subscript>Mn<subscript>0.9</subscript>Cr<subscript>0.1</subscript>O<subscript>3</subscript> perovskite manganite
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Autor/in / Beteiligte Person: | Oumezzine, Marwène ; Peña, Octavio ; Kallel, Sami ; Oumezzine, Mohamed |
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Zeitschrift: | Journal of Alloys & Compounds, Jg. 539 (2012-10-25), S. 116-123 |
Veröffentlichung: | 2012 |
Medientyp: | academicJournal |
ISSN: | 0925-8388 (print) |
DOI: | 10.1016/j.jallcom.2012.06.043 |
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