Field-Induced Spin-Flop in Antiferromagnetic Semiconductors with Commensurate and Incommensurate Magnetic Structures: Li2FeGeS4 (LIGS) and Li2FeSnS4 (LITS)

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• 作者：Jacilynn A. Brant ; Clarina dela Cruz ; Jinlei Yao ; Alexios P. Douvalis ; Thomas Bakas ; Monica Sorescu ; Jennifer A. Aitken
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：December 1, 2014
• 年：2014
• 卷：53
• 期：23
• 页码：12265-12274
• 全文大小：678K
• ISSN：1520-510X

文摘

Li₂FeGeS₄ (LIGS) and Li₂FeSnS₄ (LITS), which are among the first magnetic semiconductors with the wurtz-kesterite structure, exhibit antiferromagnetism with T_N 鈮?6 and 4 K, respectively. Both compounds undergo a conventional metamagnetic transition that is accompanied by a hysteresis; a reversible spin-flop transition is dominant. On the basis of constant-wavelength neutron powder diffraction data, we propose that LIGS and LITS exhibit collinear magnetic structures that are commensurate and incommensurate with propagation vectors k_m = [¹/₂, ¹/₂, ¹/₂] and [0, 0, 0.546(1)], respectively. The two compounds exhibit similar magnetic phase diagrams, as the critical fields are temperature-dependent. The nuclear structures of the bulk powder samples were verified using time-of-flight neutron powder diffraction along with synchrotron X-ray powder diffraction. ⁵⁷Fe and ¹¹⁹Sn M枚ssbauer spectroscopy confirmed the presence of Fe²⁺ and Sn⁴⁺ as well as the number of crystallographically unique positions. LIGS and LITS are semiconductors with indirect and direct bandgaps of 1.42 and 1.86 eV, respectively, according to optical diffuse-reflectance UV鈥搗is鈥揘IR spectroscopy.