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A new range of specific perovskite-type materials with structural, magnetic and magnetocaloric properties: La0.67Ca0.33-xSrxMn0.98Fe0.02O3 (0.15 ≤ x ≤ 0.3)
Solid State Sciences ( IF 3.5 ) Pub Date : 2021-07-13 , DOI: 10.1016/j.solidstatesciences.2021.106683
K. Laajimi 1, 2 , F. Ayadi 2 , M. Kchaw 2 , I. Fourati 2 , M. Khlifi 3 , M.H. Gazzah 1 , J. Dhahri 3 , J. Juraszek 2
Affiliation  

The effect of strontium doping on the structural, magnetic and magnetocaloric properties of La0.67Ca0.33-xSrxMn0.98Fe0.02O3 samples for (x = 0.15; 0.2.and 0.3) has been investigated. Analysis using X-ray diffraction shows there is an orthorhombic structure with Pnma space group symmetry for x = 0.15 compound, whereas there is a rhombohedral structure exhibiting R3c space group symmetry found for x = 0.2, and x = 0.3 compounds. A second-order magnetic phase transition from ferromagnetic to paramagnetic state transition is evidenced for all samples, with Curie temperature (TC) values equal to 329 K, 330 K and 350 K and that respectively for x = 0.15, 0.2 and 0.3. Based on isothermal magnetization measurements versus applied magnetic field at several temperatures around TC, the magnetic entropy change was calculated, which is very close to that approximated by the Landau theory for.x = 0.15. Under an applied magnetic field of 5 T, one can see the maximum magnetic entropy change (ΔSMmax) values, which are around 4.89, 4.71 and 3.35 J.kg− 1.K−1 for x = 0.15, 0.2, and 0.3 respectively. It confirms that close to room temperature, these manganites are admirably potential functional materials, which can be applied as solid state magnetic refrigerants.



中文翻译:

一系列具有结构、磁性和磁热特性的特定钙钛矿型材料:La 0.67 Ca 0.33- x Sr x Mn 0.98 Fe 0.02 O 3 (0.15 ≤ x ≤ 0.3)

已经研究了锶掺杂对( x  = 0.15; 0.2. 和 0.3)的 La 0.67 Ca 0.33- x Sr x Mn 0.98 Fe 0.02 O 3样品的结构、磁性和磁热性能的影响。使用 X 射线衍射的分析表明,对于x  = 0.15 的化合物,存在具有Pnma空间群对称性的正交结构,而具有显示出的菱面体结构电阻3C发现x  = 0.2 和x  = 0.3 化合物的空间群对称性。从铁磁到顺磁状态转变二阶磁相变被证明对于所有样品,用居里温度(Ť Ç)值分别等于329 K,330 K和350 K和,对于X =  0.15,0.2和0.3。基于在T C附近的几个温度下等温磁化测量值与外加磁场的关系,计算了磁熵变,这非常接近于朗道理论所近似的值。x  = 0.15。在5 T的外加磁场下,可以看到最大的磁熵变(-Δ一种X)值,对于x  = 0.15、0.2和 0.3,分别约为 4.89、4.71和 3.35 J.kg - 1 .K -1。它证实接近室温,这些锰酸盐是令人钦佩的潜在功能材料,可用作固态磁性制冷剂。

更新日期:2021-07-16
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