Critical magnetic behavior of magnetocaloric materials with the Gd5Si4-type structure
Critical magnetic behavior of magnetocaloric materials with the Gd5Si4-type structure
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DOI：
10.1063/1.4798578
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发表时间：
2013-04
影响因子：
3.2
通讯作者：
J. Belo;A. Pereira;C. Magén;L. Morellón;M. Ibarra;P. Algarabel;J. Araújo
中科院分区：
文献类型：
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作者：
J. Belo;A. Pereira;C. Magén;L. Morellón;M. Ibarra;P. Algarabel;J. Araújo
本文对稳定在Gd 5Si 4型结构中的Gd 5（SixGe 1 −x）4化合物的磁性进行了广泛的研究，重点是Gd 5Si 4和Gd 5Si 2Ge 2的组成。通过Arrott图分析，检索的自发磁化强度的温度依赖性和磁相互作用系数（Jexch）的估计。Gd_5Si_4的Jexch值比Gd_5Si_2Ge_2的高15%。这种增强不能仅仅归因于磁体积耦合，主要与（Si，Ge）-（Si，Ge）板间连接的磁极化有关。临界指数的估计（δ=3.1和2.9，γ=1.01和1.06，β=0.48和0.56，和n=0.67和0.63，分别为Gd_5Si_4和Gd_5Si_2Ge_2）表明，这两种成分属于相同的普适类。这一结论得到了M（H）等温曲线的通用对数标度图的加强。因此，我们认为Gd_5Si_4型结构化合物的磁性是由磁性引起的。
An extensive investigation on the magnetism of Gd5(SixGe1−x)4 compounds which stabilize in the Gd5Si4-type structure is here presented, focusing on the Gd5Si4 and Gd5Si2Ge2 compositions. Through Arrott plot analysis, the temperature dependencies of the spontaneous magnetizations are retrieved and the magnetic interaction coefficients (Jexch) are estimated. The obtained Jexch value for Gd5Si4 is 15% higher than that of Gd5Si2Ge2. Such enhancement cannot be attributed to a magneto-volume coupling only, being mainly associated with the magnetic polarization of the (Si,Ge)-(Si,Ge) interslab connections. The critical exponents were estimated (δ=3.1 and 2.9, γ=1.01 and 1.06, β=0.48 and 0.56, and n=0.67 and 0.63 for Gd5Si4 and Gd5Si2Ge2, respectively) demonstrating that both compositions belong to the same universal class. This conclusion is reinforced by the construction of a universal logarithmic scaling plot of the M(H) isothermal curves. Hence, we conclude that the magnetism of the Gd5Si4-type structure comp...