Itinerant ferromagnetism in the As 4$p$ conduction band of Ba$_{0.6}$K$_{0.4}$Mn$_{2}$As$_{2}$ identified by x-ray magnetic circular dichroism

B. G. Ueland; Abhishek Pandey; Y. Lee; A. Sapkota; Y. Choi; D. Haskel; R. A. Rosenberg; J. C. Lang; B. N. Harmon; D. C. Johnston; A. Kreyssig; A. I. Goldman

doi:10.1103/physrevlett.114.217001

arXiv · 1503.07197

Itinerant ferromagnetism in the As 4$p$ conduction band of Ba$_{0.6}$K$_{0.4}$Mn$_{2}$As$_{2}$ identified by x-ray magnetic circular dichroism

B. G. Ueland·Abhishek Pandey·Y. Lee·A. Sapkota·Y. Choi·D. Haskel·R. A. Rosenberg·J. C. Lang·B. N. Harmon·D. C. Johnston·A. Kreyssig·A. I. Goldman

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Abstract

X-ray magnetic circular dichroism (XMCD) measurements on single-crystal and powder samples of Ba$_{0.6}$K$_{0.4}$Mn$_{2}$As$_{2}$ show that the ferromagnetism below $T_{\textrm{C}}\approx$ 100 K arises in the As $4p$ conduction band. No XMCD signal is observed at the Mn x-ray absorption edges. Below $T_{\textrm{C}}$, however, a clear XMCD signal is found at the As $K$ edge which increases with decreasing temperature. The XMCD signal is absent in data taken with the beam directed parallel to the crystallographic $\textrm{c}$ axis indicating that the orbital magnetic moment lies in the basal plane of the tetragonal lattice. These results show that the previously reported itinerant ferromagnetism is associated with the As $4p$ conduction band and that distinct local-moment antiferromagnetism and itinerant ferromagnetism with perpendicular easy axes coexist in this compound at low temperature.

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B. G. Ueland, Abhishek Pandey, Y. Lee, A. Sapkota, Y. Choi, D. Haskel, R. A. Rosenberg, J. C. Lang, B. N. Harmon, D. C. Johnston, A. Kreyssig, A. I. Goldman. 2015-03-24. Itinerant ferromagnetism in the As 4$p$ conduction band of Ba$_{0.6}$K$_{0.4}$Mn$_{2}$As$_{2}$ identified by x-ray magnetic circular dichroism. https://doi.org/10.1103/physrevlett.114.217001

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