Stabilization of Spin and Charge Ordering in Stoichiometric YbFe2O4
Stabilization of Spin and Charge Ordering in Stoichiometric YbFe2O4
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DOI：
10.7566/jpsj.88.044701
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发表时间：
2019-04-15
影响因子：
1.7
通讯作者：
Ikeda, Naoshi
中科院分区：
文献类型：
--
作者：
Fujiwara, Kosuke;Karasudani, Tomoyuki;Ikeda, Naoshi
本文报道了铁空位控制的YbFe_2O_4晶体的宽范围倒易空间中子衍射观测结果。发现该化学计量比晶体的电荷有序转变温度升高，自旋竞争转变消失。我们推测，该晶体较低的离子缺陷促进了自旋和电荷有序相干长度的发展，从而可以检测到YbFe_2 O_4的自旋和电荷有序的内在本质。实验用二维中子探测器进行，用单斜电荷有序超晶格的六个畴成功地解释了磁有序温度T-N = 245 K以上的所有超晶格点及其调制。用极化He-3中子自旋过滤器确定了T-N以上的一个相当扩展的二维（2D）自旋关联，我们发现了T-N和300 K之间的2D自旋关联和电荷有序之间的耦合，在这个耦合处可能会出现新的晶格畸变相。
We report a wide-range reciprocal space observation with neutron diffraction in an iron vacancy controlled YbFe2O4 crystal, which is proposed as a prototype of electronic ferroelectrics arising from iron charge ordering. The increase of the charge ordering transition temperature and the disappearance of spin competitive transition were discovered in this stoichiometric crystal. We suppose that the lower ionic deficiency of this crystal enhances the development of spin and charge order coherence length, and consequently, the intrinsic nature of spin and charge ordering of YbFe2O4 could be detected. The experiment was performed with a two-dimensional neutron detector, and all super-lattice spots and its modulations above magnetic ordering temperature T-N = 245 K are successfully explained with six domains of a monoclinic charge-order super-lattice cell. A rather extended two dimensional (2D) spin correlation above T-N was identified with polarized He-3 neutron spin filter and we found a clear indication of a coupling between the 2D spin correlation and charge ordering between T-N and 300 K, at which a new lattice distortion phase may set in.