Bouguerra A, Khène S, de Brion S, Chouteau G, Fillion G
Laboratoire Louis Néel, CNRS, BP166, F-38042 Grenoble cedex 9, France. ISET, Centre Universitaire de Tebessa, 12002 Tebessa, Algeria.
J Phys Condens Matter. 2005 Jan 12;17(1):241-8. doi: 10.1088/0953-8984/17/1/023. Epub 2004 Dec 10.
High static magnetic field magnetization measurements have been performed up to 23 T on Ho(0.43)Y(2.57)Fe(5)O(12) single crystals at helium temperature (T = 4.2 K) with fields applied along the three main cubic axes: [Formula: see text], [Formula: see text] and [Formula: see text]. The change from the spontaneous ferrimagnetic structure in zero magnetic field to the fully ferromagnetic one in high field takes place through several intermediate phases separated by transitions with step-like magnetization behaviour, but without any observed hysteresis. Using the effective spin Hamiltonian approximation, we show that the general features of these transitions can be accounted for by a large magnetocristalline anisotropy of the Ho(3+) moments of the uniaxial type along the local z axis of each rare-earth site. The model is in better agreement with the experiments than its Ising limit, widely used before, but is still unsuccessful in predicting the 'umbrella' magnetic structures found by previous neutron and NMR experiments.
在氦温（T = 4.2 K）下，对Ho(0.43)Y(2.57)Fe(5)O(12)单晶施加高达23 T的高静磁场磁化强度测量，磁场沿三个主要立方轴施加：[公式：见文本]、[公式：见文本]和[公式：见文本]。从零磁场下的自发亚铁磁结构到高磁场下的完全铁磁结构的转变通过几个中间相发生，这些中间相由具有阶梯状磁化行为的转变分隔，但未观察到任何磁滞现象。利用有效自旋哈密顿近似，我们表明这些转变的一般特征可以由沿每个稀土位点的局部z轴的单轴型Ho(3+)矩的大磁晶各向异性来解释。该模型比之前广泛使用的伊辛极限与实验结果更吻合，但在预测先前中子和核磁共振实验发现的“伞状”磁结构方面仍然不成功。
