Magnetic and magnetocaloric properties of La0.85(Na1−xKx)0.15MnO3 ceramics produced by reactive spark plasma sintering
Magnetic and magnetocaloric properties of La0.85(Na1−xKx)0.15MnO3 ceramics produced by reactive spark plasma sintering
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DOI：
10.1063/1.4864138
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发表时间：
2014-02
影响因子：
3.2
通讯作者：
Y. Regaieg;L. Sicard;J. Monnier;M. Koubaa;S. Ammar-Merah;A. Cheikhrouhou
中科院分区：
文献类型：
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作者：
Y. Regaieg;L. Sicard;J. Monnier;M. Koubaa;S. Ammar-Merah;A. Cheikhrouhou
以La（OH）3、NaOH、KOH和MnO 2为原料，采用反应放电等离子烧结法合成了La0.85（Na 1 −xKx）0.15MnO3（0 ≤ x ≤ 1）陶瓷。所有化合物均以纯的、致密的和超细颗粒的形式获得。X射线粉末衍射的Rietveld精修表明，我们所合成的样品都是单相的，并且在R-3c空间群的畸变菱面体系统中结晶。它们的磁化强度在50 mT的磁场下的热变化显示出在非常接近室温的居里温度下的顺磁到铁磁的转变。由磁化强度测量结果推导出的磁熵变在几个温度下随外加磁场的变化呈现出最大值|ΔSM| max随K含量的增加而略有增加。根据以下公式推导出的相对冷却功率值|ΔSM|相对于T峰展宽，随钾含量略有变化，在5.
La0.85(Na1−xKx)0.15MnO3 (0 ≤ x ≤ 1) ceramics were synthesized from the raw La(OH)3, NaOH, KOH, and MnO2 powders using Reactive Spark Plasma Sintering. All the compounds were obtained as pure, dense, and ultrafine grained pellets. The Rietveld refinement of the X-Ray powder diffraction shows that all our synthesized samples are single phase and crystallize in the distorted rhombohedral system with R-3c space group. The thermal variation of their magnetization under a magnetic applied field of 50 mT shows a paramagnetic to ferromagnetic transition at a Curie temperature very close to room temperature. The magnetic entropy change, deduced from magnetization measurements versus magnetic applied field up to 5 T at several temperatures exhibits a maximum |ΔSM|max which slightly increases with increasing K content. The relative cooling power values, inferred from the |ΔSM| vs T peak broadening, vary slightly with the potassium content, reaching, values between 316 and 289 Jkg−1, in an applied magnetic field of 5...