Nature of the transition between a ferromagnetic metal and a spin-glass insulator in pyrochlore molybdates
Nature of the transition between a ferromagnetic metal and a spin-glass insulator in pyrochlore molybdates
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DOI：
10.1103/physrevlett.99.086401
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发表时间：
2007-08-24
影响因子：
8.6
通讯作者：
Tokura, Y.
中科院分区：
文献类型：
--
作者：
Hanasaki, N.;Watanabe, K.;Tokura, Y.
本文研究了烧绿石钼酸盐R_2Mo_2O_7与稀土离子R的金属-绝缘体转变。对交流磁化率的动力学标度分析表明，原子的自旋玻璃态是由几何阻挫引起的。重入自旋玻璃相存在于铁磁转变之下。与能带计算结果相比，电子比热有所提高，这可能是由于半金属铁磁态的轨道涨落。大的比热在转变时反而降低，可能是因为短程反铁磁涨落收缩了费米面。
The metal-insulator transition has been investigated for pyrochlore molybdates R2Mo2O7 with nonmagnetic rare-earth ions R. The dynamical scaling analysis of ac susceptibility reveals that the geometrical frustration causes the atomic spin-glass state. The reentrant spin-glass phase exists below the ferromagnetic transition. The electronic specific heat is enhanced as compared to the band calculation result, perhaps due to the orbital fluctuation in the half-metallic ferromagnetic state. The large specific heat is rather reduced upon the transition, likely because the short-range antiferromagnetic fluctuation shrinks the Fermi surface.