title: The Magnetic and Crystal Structure of MnxGa (1.15 ≤ x ≤ 1.8) Alloys.
abstract: Neutron powder diffraction patterns measured above TChave been used to determine the location of the excess Mn in MnxGa (1.15 ≤ x ≤ 1.8). This information has then been used to constrain the fits to neutron powder diffraction patterns measured at ambient temperature and so determine unambiguously the Mn moments in this system. We find that Mn randomly occupies the two Ga sites (2a and 2b) in the I4/mmm structure and propose that it is more appropriate to use a simpler structure based on the P4/mmm space group with a reduced unit cell. In this structure the two Ga sites are formally equivalent (they occupy the 1a site while Mn occupies the 1d site). Our experimental observations are supported by DFT calculations. Below TCwe find that the Mn(1d) moment is constant at 2.45(3) μB, while Mn on the 1a site carries a slightly larger moment (~3 μB) that is coupled antiparallel to the Mn(1d) moments, leading to the observed drop in magnetisation with increasing Mn content in MnxGa.
authors.affiliation: Physics Department and Centre for the Physics of Materials, McGill University, 3600 University Street, Montreal, Quebec, H3A 2T8, Canada.
authors.forename: D H
authors.initials: DH
authors.lastname: Ryan
authors.affiliation: College of Materials Science and Engineering, Beijing University of Technology, Beijing, 100122, China. yueming@bjut.edu.cn.
authors.forename: Ming
authors.initials: M
authors.lastname: Yue
authors.affiliation: Canadian Neutron Beam Centre, Chalk River Laboratories, Ontario, K0J 1J0, Canada.
authors.forename: C B
authors.identifier: http://orcid.org/0000-0003-1693-6033
authors.initials: CB
authors.lastname: Boyer
authors.affiliation: Physics Department and Centre for the Physics of Materials, McGill University, 3600 University Street, Montreal, Quebec, H3A 2T8, Canada.
authors.forename: X B
authors.initials: XB
authors.lastname: Liu
authors.affiliation: College of Materials Science and Engineering, Beijing University of Technology, Beijing, 100122, China.
authors.forename: Qingmei
authors.initials: Q
authors.lastname: Lu
authors.affiliation: College of Materials Science and Engineering, Beijing University of Technology, Beijing, 100122, China.
authors.forename: Hongguo
authors.initials: H
authors.lastname: Zhang
authors.affiliation: College of Materials Science and Engineering, Beijing University of Technology, Beijing, 100122, China.
authors.forename: Chenhui
authors.initials: C
authors.lastname: Li
authors.affiliation: College of Materials Science and Engineering, Beijing University of Technology, Beijing, 100122, China.
authors.forename: Manli
authors.initials: M
authors.lastname: Wang
authors.affiliation: Physics Department and Centre for the Physics of Materials, McGill University, 3600 University Street, Montreal, Quebec, H3A 2T8, Canada.
authors.forename: Z
authors.initials: Z
authors.lastname: Altounian