Itinerant Ferromagnetism in the As 4p Conduction Band of Ba0.6K0.4Mn2As2 Identified by X-Ray Magnetic Circular Dichroism

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

来源：Physical Review Letters, 2015, 114(21): 217001.

DOI：10.1103/PhysRevLett.114.217001

X-ray magnetic circular dichroism (XMCD) measurements on single-crystal and powder samples of Ba0.6K0.4Mn2As2 show that the ferromagnetism below T-C approximate to 100 K arises in the As 4p conduction band. No XMCD signal is observed at the Mn x-ray absorption edges. Below T-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 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