Critical scaling analysis of the itinerant ferromagnet Sr 1 − x Ca x RuO 3
Critical scaling analysis of the itinerant ferromagnet Sr 1 − x Ca x RuO 3
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DOI：
10.1103/physrevb.89.174405
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发表时间：
2014-05
影响因子：
3.7
通讯作者：
D. Fuchs;M. Wissinger;J. Schmalian;C. L. Huang;R. Fromknecht;R. Schneider;H. Löhneysen
中科院分区：
文献类型：
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作者：
D. Fuchs;M. Wissinger;J. Schmalian;C. L. Huang;R. Fromknecht;R. Schneider;H. Löhneysen
基于Arrott-Noakes状态方程的标度分析研究了Sr 1 − xCaxRuO 3的临界行为。提取了0 × 0.6样品的磁临界行为的临界指数β、γ和δ。铁磁系统表现出一个平稳的抑制居里温度TC为零，在临界浓度xc 0.7。有序的磁矩减少同时预期巡回铁磁体，但是，并没有完全消失在xc，表明小磁簇或不均匀性。当x = 0时，观察到类平均场指数。随着x的增加，临界指数β、γ和δ从β 0.5、γ 1和δ 3或x = 0到β 1、γ 0.9和δ 1.6（x 0.6）几乎呈线性变化。Widom比例关系总是满足x 0.6。尽管临界指数作为x的函数有系统的演化，但这些指数不能用任何已知的经典标准模型的普适类来描述。有效临界指数的特定趋势可能由固定点的强无序线解释; xc附近表明这种行为是由量子相变附近引起的。
The critical behavior of Sr1−xCaxRuO3 was investigated by a scaling analysis based on the Arrott-Noakes equation of state. The critical exponents β, γ ,a ndδ of the magnetic critical behavior were extracted for samples with 0 x 0.6 . The ferromagnetic system exhibits a smooth suppression of the Curie temperature TC to zero at a critical concentration xc 0.7. The ordered magnetic moment decreases simultaneously as expected for itinerant ferromagnets, however, does not vanish completely at xc, indicating small magnetic clusters or inhomogeneities. For x = 0, mean-field like exponents are observed. With increasing x, the critical exponents β, γ ,a ndδ vary nearly linearly from β 0.5, γ 1, and δ 3f orx = 0t oβ 1, γ 0.9, and δ 1.6 for x 0.6. The Widom scaling relation is always met for x 0.6. Despite the systematic evolution of the critical exponents as a function of x, the exponents cannot be described by any of the universality classes known for classical standard models. The particular trend of the effective critical exponents may be possibly explained by a strong-disorder line of fixed points; the vicinity to xc suggests that this behavior is caused by the vicinity to a quantum phase transition.