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首页> 外文期刊>RSC Advances >Effect of strontium deficiency on the structural, magnetic and magnetocaloric properties of La0.65Eu0.05Sr0.3-xMnO3 (0 <= x <= 0.15) perovskites
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Effect of strontium deficiency on the structural, magnetic and magnetocaloric properties of La0.65Eu0.05Sr0.3-xMnO3 (0 <= x <= 0.15) perovskites

机译：锶缺乏对La0.65Eu0.05Sr0.3-xMnO3（0 <= x <= 0.15）钙钛矿的结构，磁性和磁热性质的影响

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摘要

We have investigated the effect of nominal strontium deficiency on the structure, magnetic and magnetocaloric properties of La0.65Eu0.05Sr0.3-xMnO3 (x = 0, 0.10 and 0.15) perovskites. The nanocrystalline samples were prepared by the sol-gel-based Pechini method. Rietveld refinement of the X-ray diffraction patterns, shows the formation of single-phase compositions with rhombohedral symmetry (space group R (3) over barc, no. 167). Raman spectra at room temperature reveal a gradual change in phonon modes with increasing nominal strontium deficiency. All the samples undergo paramagnetic-ferromagnetic (PM-FM) transition. The Curie temperature decreases linearly with increasing x and changes from 355 K for x = 0 to 280 K for x = 0.15. Arrott plot analyses and a universal curve method were applied for studying the order of the magnetic transition in this system, found to be of second order. As strontium deficiency content increased further, peak entropy values were seen to decline. However, a simultaneous broadening of the Delta S-M(max) peaks led to enhanced relative cooling power (RCP) in the Sr-deficiency samples of up to 22% over that of La0.65Eu0.05Sr0.3MnO3. La0.65Eu0.05Sr0.15MnO3 exhibits the largest RCP value of 283 J kg(-1) at 280 K among the compounds investigated up to 5 T applied field. Through these results, La0.65Eu0.05Sr0.3-xMnO3 materials are strongly suggested for use as active refrigerants for magnetic refrigeration technology near and above room temperature.
机译：我们研究了名义锶缺乏对La0.65Eu0.05Sr0.3-xMnO3（x = 0、0.10和0.15）钙钛矿的结构，磁热磁性能的影响。纳米晶体样品是通过基于溶胶凝胶的Pechini方法制备的。 X射线衍射图的Rietveld精炼显示具有菱面体对称性的单相组合物的形成（Rc上的空间群R（3），编号167）。室温下的拉曼光谱表明，声子模态随着标称锶缺乏量的增加而逐渐变化。所有样品都经历顺磁性-铁磁性（PM-FM）转变。居里温度随x的增加线性降低，从x = 0的355 K变为x = 0.15的280K。应用Arrott图分析和通用曲线方法来研究该系统中的磁跃迁阶次，发现该阶跃次阶为2阶。随着锶缺乏含量的进一步增加，峰值熵值下降。但是，同时展宽Delta S-M（max）峰导致Sr缺乏样品中的相对冷却功率（RCP）比La0.65Eu0.05Sr0.3MnO3增强了22％。 La0.65Eu0.05Sr0.15MnO3在280 K下显示的最大RCP值为283 J kg（-1），在最多5 T的应用领域中进行了研究。通过这些结果，强烈建议将La0.65Eu0.05Sr0.3-xMnO3材料用作接近或高于室温的磁性制冷技术的活性制冷剂。

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