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arXiv 1407.2184cond-mat.str-elcond-mat.mtrl-sci
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DyRuAsO中的竞争磁相和场致动力学

Competing magnetic phases and field-induced dynamics in DyRuAsO

Michael A. McGuire, V. Ovidiu Garlea, Andrew F. May, Brian C. Sales

摘要:

本文分析了DyRuAsO在外加磁场中的中子衍射、直流磁化强度、交流磁化率、热容和电阻率,温度接近或低于发生结构畸变(T_S = 25 K)和随后的磁有序化(T_N = 10.5 K)的温度。粉末中子衍射被用来确定反铁磁顺序的Dy的磁矩的大小为7.6(1)μ B的情况下,磁场,并证明了重新取向的力矩成铁磁配置后,应用磁场。Dy磁性被确定为结构变形的驱动力。还报道了类似TbRuAsO的磁性结构。在低温下外加磁场中,DyRuAsO中两种磁有序态之间的竞争产生了不寻常的物理性质。在T* = 3 K附近观察到一个额外的相变,在大于约3 T的磁场中,在热容和其他性质中观察到。这种量级的磁场还诱导自旋玻璃状行为,包括热和磁滞、零场冷却和场冷却磁化的发散、交流磁化率中的频率依赖异常以及磁化的缓慢弛豫。这是值得注意的,因为DyRuAsO是一种化学计量材料,中子衍射没有检测到无序,并建议与自旋冰化合物和相关材料具有强烈的几何挫折的类比。

英文摘要:

Analysis of neutron diffraction, dc magnetization, ac magnetic susceptibility, heat capacity, and electrical resistivity for DyRuAsO in an applied magnetic field are presented at temperatures near and below those at which the structural distortion (T_S = 25 K) and subsequent magnetic ordering (T_N = 10.5 K) take place. Powder neutron diffraction is used to determine the antiferromagnetic order of Dy moments of magnitude 7.6(1) mu_B in the absence of a magnetic field, and demonstrate the reorientation of the moments into a ferromagnetic configuration upon application of a magnetic field. Dy magnetism is identified as the driving force for the structural distortion. The magnetic structure of analogous TbRuAsO is also reported. Competition between the two magnetically ordered states in DyRuAsO is found to produce unusual physical properties in applied magnetic fields at low temperature. An additional phase transition near T* = 3 K is observed in heat capacity and other properties in fields greater than about 3 T. Magnetic fields of this magnitude also induce spin-glass-like behavior including thermal and magnetic hysteresis, divergence of zero-field-cooled and field-cooled magnetization, frequency dependent anomalies in ac magnetic susceptibility, and slow relaxation of the magnetization. This is remarkable since DyRuAsO is a stoichiometric material with no disorder detected by neutron diffraction, and suggests analogies with spin-ice compounds and related materials with strong geometric frustration.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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