title: Collinear antiferromagnetism in trigonal SrMn2As2revealed by single-crystal neutron diffraction.
abstract: Iron pnictides and related materials have been a topic of intense research for understanding the complex interplay between magnetism and superconductivity. Here we report on the magnetic structure of SrMn2As2that crystallizes in a trigonal structure ([Formula: see text]) and undergoes an antiferromagnetic (AFM) transition at [Formula: see text] K. The magnetic susceptibility remains nearly constant at temperatures [Formula: see text] with [Formula: see text] whereas it decreases significantly with [Formula: see text]. This shows that the ordered Mn moments lie in the [Formula: see text] plane instead of aligning along the [Formula: see text]-axis as in tetragonal BaMn2As2. Single-crystal neutron diffraction measurements on SrMn2As2demonstrate that the Mn moments are ordered in a collinear Néel AFM phase with [Formula: see text] AFM alignment between a moment and all nearest neighbor moments in the basal plane and also perpendicular to it. Moreover, quasi-two-dimensional AFM order is manifested in SrMn2As2as evident from the temperature dependence of the order parameter.
authors.affiliation: Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA.
authors.forename: Pinaki
authors.initials: P
authors.lastname: Das
authors.forename: N S
authors.initials: NS
authors.lastname: Sangeetha
authors.forename: Abhishek
authors.initials: A
authors.lastname: Pandey
authors.forename: Zackery A
authors.initials: ZA
authors.lastname: Benson
authors.forename: T W
authors.initials: TW
authors.lastname: Heitmann
authors.forename: D C
authors.initials: DC
authors.lastname: Johnston
authors.forename: A I
authors.initials: AI
authors.lastname: Goldman
authors.forename: A
authors.initials: A
authors.lastname: Kreyssig