Open AccessGeneral nature of the step-induced frustration at ferromagnetic/antiferromagnetic interfaces: topological origin and quantitative understanding
Author(s) -
Xiaojia Chen,
Tianhao Ji,
Limei Sun,
Bingfeng Miao,
Y. T. Millev,
Haifeng Ding
Publication year - 2019
Publication title -
new journal of physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.584
H-Index - 190
ISSN - 1367-2630
DOI - 10.1088/1367-2630/ab5cbd
Subject(s) - antiferromagnetism , condensed matter physics , frustration , physics , ferromagnetism , domain wall (magnetism) , anisotropy , monatomic ion , magnetic domain , domain (mathematical analysis) , heisenberg model , optics , magnetization , quantum mechanics , magnetic field , mathematics , mathematical analysis
We present a study of the magnetic configuration due to step-induced magnetic frustration at ferromagnetic/antiferromagnetic (FM/AFM) interfaces. At a substrate monatomic step edge, a 180° domain wall emerges. A physically appealing form for the thickness dependence of the domain wall width is obtained. It follows a universal behaviour in the whole thickness range, from ultrathin film to bulk and in both cases of an AFM domain wall on top of the FM layer and a FM domain wall on top of an AFM substrate. In the ultrathin limit of the capping layer, the domain wall grows linearly with the slope depending only on the ratio of the inter-layer and intra-layer Heisenberg exchange constants, regardless of the presence of magneto-crystalline anisotropy. These findings are in good agreement with previous experimental observations. As the thickness grows beyond the ultrathin regime, the corresponding thickness dependence departs from linearity and tends to its bulk value. The analytical insights are supported by conclusive numerical simulations of two independent varieties, namely, the Monte Carlo method which also includes the growth kinetics and the object oriented micromagnetic framework based micromagnetic simulations. While the quantitative details of the study are naturally dependent on the specific material parameters of the complex magnetic system, the global features of the spin texture in the capping layer are dictated by the topological step-edge defect. The latter in itself is quantifiable by a winding number of ± 1 2 .