Structural, magnetic, and electronic evolution of the spin-ladder system BaFe2S3–xSex with isoelectronic substitution
Structural, magnetic, and electronic evolution of the spin-ladder system BaFe2S3–xSex with isoelectronic substitution
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具有等电子取代的自旋梯系统 BaFe2S3-xSex 的结构、磁性和电子演化
DOI：
10.1103/physrevb.101.235134
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发表时间：
2020-06
期刊：
影响因子：
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通讯作者：
Birgeneau RJ
中科院分区：
文献类型：
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作者：
Yu J;Wang M;Frandsen BA;Sun H;Yin J;Liu Z;Wu S;Yi M;Xu Z;Acharya A;Huang Q;Bourret-Courchesne E;Lynn JW;Birgeneau RJ
报道了一系列BaFe2S3-xSex(0⩽x⩽3)单晶和粉末样品的X射线衍射、中子衍射、介子自旋驰豫和电输运测量的实验研究。在x=0.7-1附近发现了从CMCM(BaFe2S3)到Pnma(BaFe2Se3)的结构转变。对x=0.2、0.4和0.7的样品进行的中子衍射测量表明，条状反铁磁序的Néel温度在~120~85K之间逐渐降低，而有序Fe2+磁矩的大小变化很小。同样，BaFe_2Se_3中的块状反铁磁序在1.5⩽x⩽_3中保持稳定，有序矩变化可以忽略不计，Néel温度从250K(x=3)略降至225K(x=1.5)。在CMCM和PnMA边界附近，x=1的样品表现出二维、短程条状和块状的反铁磁关联共存。系统对所有的x都保持绝缘性，但当从CMCM条状相到Pnma块状相穿过边界时，热激活能隙突然增加。结果表明，BaFe2S3-xSex体系的晶体结构、磁序和电子性质是强耦合的。
We report experimental studies of a series of BaFe2S3–xSex (0 ⩽ x ⩽ 3) single crystals and powder specimens using x-ray diffraction, neutron-diffraction, muon-spin-relaxation, and electrical transport measurements. A structural transformation from Cmcm (BaFe2S3) to Pnma (BaFe2Se3) was identified around x = 0.7 – 1. Neutron-diffraction measurements on the samples with x = 0.2, 0.4, and 0.7 reveal that the Néel temperature of the stripe antiferromagnetic order is gradually suppressed from ~120 to 85 K, while the magnitude of the ordered Fe2+ moments shows very little variation. Similarly, the block antiferromagnetic order in BaFe2Se3 remains robust for 1.5 ⩽ x ⩽ 3 with negligible variation in the ordered moment and a slight decrease of the Néel temperature from 250 K (x = 3) to 225 K (x = 1.5). The sample with x = 1 near the Cmcm and Pnma border shows coexisting, two-dimensional, short-range stripe- and block-type antiferromagnetic correlations. The system remains insulating for all x, but the thermal activation gap shows an abrupt increase when traversing the boundary from the Cmcm stripe phase to the Pnma block phase. The results demonstrate that the crystal structure, magnetic order, and electronic properties are strongly coupled in the BaFe2S3–xSex system.