Comparative study of the field-induced and spontaneous AF2′ multiferroic phases in MnWO₄ and Mn_0.90Co_0.10WO₄ within the magnetic symmetry framework

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• 作者：Irene Urcelay-Olabarria ; José ; Luis Garcí ; a-Mu&ntilde ; oz ; Eric Ressouche ; Alexander A. Mukhin and Vassil Skumryev
• 关键词：(Mn ; Co)WO4 compounds ; multiferroic phases ; magnetic symmetry framework ; incommensurate magnetic orders
• 刊名：Journal of Applied Crystallography
• 出版年：2016
• 出版时间：April 2016
• 年：2016
• 卷：49
• 期：2
• 页码：520-527
• 全文大小：553K
• ISSN：1600-5767

文摘

(Mn,Co)WO₄ compounds are regarded as reference spin-induced multiferroics. A comparative study is presented here, within the magnetic symmetry framework, of the incommensurate magnetic orders responsible for the ferroelectric phases of (i) MnWO₄ under a magnetic field (H || b) and (ii) Mn_0.90Co_0.10WO₄ in the absence of an external field. On the one hand, although these two ferroelectric phases are stabilized under different external physical conditions, both present the same Xc1′(α0γ)ss magnetic symmetry and practically the same modulation vector. The magnetic ordering in both phases is an elliptical helix with the magnetic moments (as the polarization vector, P) perpendicular to the b axis, although in most of the ferroelectric compositions of the (Mn,Co)WO₄ family the spins rotate in planes containing b (and have P || b). On the other hand, the anisotropy of the resulting magnetic modulations is extraordinarily different in the two phases. This is described and explained in the light of the different anisotropies of Co and Mn ions.