View in EDS

Crossover of the magnetocaloric effect and its importance on the determination of the critical behaviour in the La0.67Ba0.33Mn0.9Cr0.1O3 perovskite manganite

Saved in:
Bibliographic Details
Title: Crossover of the magnetocaloric effect and its importance on the determination of the critical behaviour in the La0.67Ba0.33Mn0.9Cr0.1O3 perovskite manganite
Authors: Oumezzine, Marwène1,2 marouan.omezzine@etudiant.univ-rennes1.fr, Peña, Octavio2, Kallel, Sami1, Oumezzine, Mohamed1
Source: Journal of Alloys & Compounds. Oct2012, Vol. 539, p116-123. 8p.
Subjects: Perovskite, Lanthanum compounds, Manganite, Phase transitions, Entropy, Magnetization, Curie temperature
Abstract: 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]
Copyright of Journal of Alloys & Compounds is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Engineering Source
Description
Abstract: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]
ISSN:09258388
DOI:10.1016/j.jallcom.2012.06.043