Neutron Laue diffraction study of the complex low-temperature magnetic behaviour of brownmillerite-type Ca2Fe2O5
Neutron Laue diffraction study of the complex low-temperature magnetic behaviour of brownmillerite-type Ca2Fe2O5
复制标题
褐针矿型Ca2Fe2O5复杂低温磁行为的中子劳厄衍射研究
DOI：
10.1107/s1600576714027976
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发表时间：
2015
影响因子：
6.1
通讯作者：
C. Ling
中科院分区：
文献类型：
--
作者：
J. Auckett;G. McIntyre;M. Avdeev;H. D. Bruyn;T. Tan;Sean Li;C. Ling
褐针铁矿 Ca2Fe2O5 的原子和磁性结构已根据零场和低磁场 (35 Oe = 35 × 103/4π A m−1) 条件下在 300、100 和 10 K 收集的单晶中子劳厄衍射数据进行了细化。 Ca2Fe2O5 是一种倾斜的 G 型反铁磁体，具有 Pcm'n' 对称性，室温下 Fe 上的磁矩大致沿晶体 c 轴方向。细化结果清楚地表明，这种磁结构持续到 T = 10 K，尽管之前有人提出，在 Ca2Fe2O5 单晶中在 40 到 140 K 之间观察到的异常磁化率增强可能意味着反铁磁易磁化轴从 c 重新定向到低于 40 K。对于这种磁化率异常的替代解释是根据部分或短程的证据来考虑的。异常状态中的秩序丧失，可能是由于存在多个竞争性亚晶格相互作用。
The atomic and magnetic structure of brownmillerite Ca2Fe2O5 has been refined against single-crystal neutron Laue diffraction data collected at 300, 100 and 10 K under zero-field and low-magnetic field (35 Oe = 35 × 103/4π A m−1) conditions. Ca2Fe2O5 is a canted G-type antiferromagnet with Pcm′n′ symmetry, the magnetic moments on Fe being directed approximately along the crystallographic c axis at room temperature. The refinement results show clearly that this magnetic structure persists down to T = 10 K, despite a previous suggestion that an anomalous magnetic susceptibility enhancement observed in Ca2Fe2O5 single crystals between 40 and 140 K might signify a reorientation of the antiferromagnetic easy axis from c to a below 40 K. Alternative explanations for this susceptibility anomaly are considered in terms of the evidence for partial or short-range loss of order in the anomalous regime, possibly due to the presence of multiple competing sublattice interactions.