Magnetic structure of hexagonalRMnO3(R=Y,Sc):Thermal evolution from neutron powder diffraction data
Magnetic structure of hexagonalRMnO3(R=Y,Sc):Thermal evolution from neutron powder diffraction data
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DOI：
10.1103/physrevb.62.9498
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发表时间：
2000-10
影响因子：
3.7
通讯作者：
A. Muñoz;J. Alonso;M. J. Martínez-Lope;M. T. Casais;J. Martínez;M. Fernández-Díaz
中科院分区：
文献类型：
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作者：
A. Muñoz;J. Alonso;M. J. Martínez-Lope;M. T. Casais;J. Martínez;M. Fernández-Díaz
通过粉末样品的中子衍射实验，研究了六方晶系YMnO_3和ScMnO_3氧化物(空间群P_(63)cm)的磁结构。这项研究还得到了磁化率和比热测量的补充。它们证实了YMnO3和ScMnO3分别在T N≈70K和T N≈12 9K以下按三角形反铁磁结构有序化。后一种化合物在75K以下经历第二次磁相变，对应于自旋重新取向。在Sc材料的所有有序区域都观察到了Dzialoshinskii-Moriya类型的弱铁磁性。在这两种化合物中，力矩都包含在(a，b)平面内，并与[100]方向垂直(R=Y)或平行(R=SC)。在T=1.7K时的低温有序矩分别为2.90(2)μB(R=Y)和3.54(3)μB(R=Sc)。根据由高分辨结构数据确定的几何参数，讨论了这两种化合物磁结构热演化的不同行为。分析了ScMnO_3中铁磁性较弱的原因。
The magnetic structures of the hexagonal YMnO 3 and ScMnO 3 oxides (space group P 6 3 c m) have been studied by neutron-diffraction experiments on powder samples. This study has been complemented with magnetic susceptibility and specific-heat measurements. They confirm that YMnO 3 and ScMnO 3 become ordered below T N≈ 70 K and T N≈ 129 K, respectively, according to a triangular antiferromagnetic structure. The latter compound undergoes a second magnetic transition below 75 K, corresponding to a spin reorientation. The presence of weak ferromagnetism of Dzialoshinskii-Moriya type is observed in all the ordered region for the Sc material. In both compounds the moments are contained in the (a, b) plane and oriented perpendicular (R= Y) or parallel (R= Sc) to the [100] directions. The low-temperature ordered moments are 2.90 (2) μ B (R= Y) and 3.54 (3) μ B (R= Sc) at T= 1.7 K. The different behavior observed in the thermal evolution of the magnetic structure of both compounds is discussed in terms of geometrical parameters determined from high-resolution structural data. The origin of the weak ferromagnetism in ScMnO 3 is also analyzed.