Hydrogenation inducing antiferromagnetism in the heavy-fermion ternary silicide CeRuSi
Hydrogenation inducing antiferromagnetism in the heavy-fermion ternary silicide CeRuSi
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DOI：
10.1103/physrevb.77.014414
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发表时间：
2008-01-01
影响因子：
3.7
通讯作者：
Coqblin, B.
中科院分区：
文献类型：
--
作者：
Chevalier, B.;Gaudin, E.;Coqblin, B.
将重费米子三元硅化物CeRuSi在4 MPa氢气气氛中于523 K下热暴露，合成了空间群为P4/nmm的氢化物CeRuSiH1.0。氢化物的X-射线粉末衍射研究表明，氢化诱导了明显的各向异性膨胀的晶胞。此外，CeRuSiH 1.0在T-N1=7.5（2）K和T-N2=3.1（2）K处存在两个反铁磁转变。氢化将中等重费米子化合物CeRuSi（γ =220 mJ/mol K-2）改变为反铁磁体，其具有较小的电子系数γ =26 mJ/mol K-2。换句话说，氢的插入减弱了近藤效应的影响。过渡重费米子行为->反铁磁体可以很好地理解在经典的Doniach图，其中氢化的作用与压力相反。在这里，由氢插入引起的晶格膨胀比在其他氢化化合物CeCoSiH1.0或CeCoGeH1.0中观察到的Ce-H键合的作用重要得多，在其他氢化化合物中证明了相反的转变（反铁磁->自旋波动）。
The hydride CeRuSiH1.0 with space group P4/nmm was synthesized by exposure at 523 K of the heavy-fermion ternary silicide CeRuSi under 4 MPa of hydrogen gas. The investigation of the hydride by x-ray powder diffraction reveals that the hydrogenation induces a pronounced anisotropic expansion of the unit cell. Moreover, CeRuSiH1.0 presents two antiferromagnetic transitions at T-N1=7.5(2) K and T-N2=3.1(2) K evidenced by magnetization and specific heat measurements. Hydrogenation changes the moderate heavy-fermion compound CeRuSi, which has a gamma=220 mJ/mol K-2, to an antiferromagnet, which has a smaller electronic coefficient gamma=26 mJ/mol K-2. In other words, the hydrogen insertion diminishes the influence of the Kondo effect. The transition heavy-fermion behavior -> antiferromagnet can be well understood in terms of the classical Doniach diagram where the hydrogenation plays a role opposite to the pressure. The expansion of the lattice induced by hydrogen insertion is here much more important than the role of Ce-H bonding observed in other hydrogenated compounds CeCoSiH1.0 or CeCoGeH1.0, where an opposite transition (antiferromagnetic -> spin fluctuation) was evidenced.