Structural, magnetic and magnetocaloric properties of the lanthanum deficient in La0.8Ca0.2-x▭xMnO3 (x=0-0.20) manganites oxides
Structural, magnetic and magnetocaloric properties of the lanthanum deficient in La0.8Ca0.2-x▭xMnO3 (x=0-0.20) manganites oxides
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DOI：
10.1016/j.jallcom.2011.04.049
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发表时间：
2011-07-07
影响因子：
6.2
通讯作者：
Hlil, E. K.
中科院分区：
文献类型：
--
作者：
Khlifi, M.;Bejar, M.;Hlil, E. K.
通过固相反应制备了La0.8Ca0.2-x矩形xMnO3， （x = 0-0.20）化合物。利用x射线衍射（XRD）和磁性测量研究了钙空位对材料物理性质的影响。采用Rietveld细化技术对XRD数据进行了分析。当x = 0、0.05和0.10时，样品为单相，并与Pnma空间群呈正交对称结晶。此外，对于x = 0.15和0.20的样品，细化发现pma正方和R(3)共存于barc菱面体相。磁性研究表明，磁化强度在x = 0.15时最大，在x = 0.2时最小。这种行为可以用正交畸变贡献来解释，这与正交结构有关，导致磁化强度降低。此外，在5 T的外加磁场下，x = 0样品的最大磁熵变（δ S-M）可达4.1 J/kgK，这对于磁制冷的潜在应用是非常充分的。对于相同的外加磁场（μ H-0= 5 T），相对冷却功率（RCP）值在270 ~ 300 J/kg之间变化。因此，La0.8Ca0.2-x矩形xMnO3化合物可以在[175-183]K温度范围内用作磁致冷的复合材料。(C) 2011 Elsevier B.V.版权所有
The La0.8Ca0.2-x rectangle xMnO3, (x = 0-0.20) compounds were prepared by the solid-state reaction. X-ray diffraction (XRD) and magnetic measurements were used to investigate the calcium-vacancy effect on the physical properties. The XRD data have been analyzed by Rietveld refinement technique. Samples with x = 0, 0.05 and 0.10 are found to be single phase and crystallize in orthorhombic symmetry with Pnma space group. Moreover, for x = 0.15 and 0.20 samples, the refinement has revealed the coexistence of both Pnma orthorhombic and R (3) over barc rhombohedral phases. The magnetic study has showed that the magnetization exhibits maximum at x = 0.15 and minimum at x = 0.2. Such behavior was interpreted in terms of orthorhombic distortion contribution, which is related to the orthorhombic structure, leading to magnetization decrease. In addition, maximum magnetic entropy change (Delta S-M) for x = 0 sample was found to reach similar to 4.1 J/kgK under an applied magnetic field of 5 T, which is very sufficient for potential application in magnetic refrigeration. For the same applied magnetic field (mu H-0= 5 T), the Relative Cooling Power (RCP) values are found to vary between 270 and 300 J/kg. As consequence, the La0.8Ca0.2-x rectangle xMnO3 compounds can be used as a composite for magnetic refrigeration in the [175-183] K temperature range. (C) 2011 Elsevier B.V. All rights reserved.