First principles calculation of magnetic order in a low-temperature phase of the iron ludwigite

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:374

Article

Matos, M.¹  Terra, J.²  Ellis, D. E.^2,3  Pimentel, A. S.⁴ 

[1] Pontificia Univ Catolica Rio de Janeiro, Dept Fis, BR-22453970 Rio de Janeiro, RJ, Brazil

[2] Ctr Braisileiro Pesquisas Fis, Rio De Janeiro, RJ, Brazil

[3] Northwestern Univ, Evanston, IL USA

[4] Pontificia Univ Catolica Rio de Janeiro, Dept Quim, BR-22453970 Rio de Janeiro, RJ, Brazil

关键词: Fe ludwigite;    Theory;    DFT;    Non-collinear spin;    Magnetic order;   

DOI  :  10.1016/j.jmmm.2014.08.025

来源: Elsevier

【 摘 要 】

The magnetic order of a low-temperature dimerized phase of Fe3O2BO3 is investigated through a density Functional approach which considers full non-collinear spin-spin interactions, focusing on the 15 K crystalline structure. It is found that Fe spins in the (Fe-Fe)(5+) dimer, formed during the room temperature structural change or Fe3O2BO3, are parallel and have little freedom to rotate under interaction with neighbor Fe atoms. While the Fe dimer behaves as a heavy single magnetic unit the spin magnetic moment of the third Fe3+ atom of the Fe triad has, on the contrary, much more freedom to rotate. This is responsible for a canted spin ordering, revealed by a rotation of similar to 80 degrees of the trivalent Fe spin relative to the spin orientation of the dimer, due to spin-spin interaction with divalent Fe atoms outside the triad. Canting is thus seen to be responsible for the very low net magnetization, experimentally observed in this compound (T< 40 K). (c) 2014 Elsevier B.V. All rights reserved.

【 授权许可】

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