title: Magnetic ordering in TmGa.
abstract: We have determined the magnetic structure of the intermetallic compound TmGa by high-resolution neutron powder diffraction and (169)Tm Mössbauer spectroscopy. This compound crystallizes in the orthorhombic (Cmcm) CrB-type structure and its magnetic structure is characterized by magnetic order of the Tm sublattice along the a-axis. The initial magnetic ordering occurs at 15(1) K and yields an incommensurate antiferromagnetic structure described by the propagation vector k1 = [0 0.275(2) 0]. At 12 K the dominant ferromagnetic ordering of the Tm sublattice along the a-axis develops in what appears to be a first-order transition. At 3 K the magnetic structure of TmGa is predominantly ferromagnetic but a weakened incommensurate component remains. The ferromagnetic Tm moment reaches 6.7(2) μB at 3 K and the amplitude of the remaining incommensurate component is 2.7(4) μB. The (169)Tm hyperfine magnetic field at 5 K is 631(1) T.
authors.affiliation: School of Physical, Environmental and Mathematical Sciences, UNSW Canberra at the Australian Defence Force Academy, Canberra, ACT, BC 2610, Australia.
authors.forename: J M
authors.initials: JM
authors.lastname: Cadogan
authors.forename: G A
authors.initials: GA
authors.lastname: Stewart
authors.forename: S
authors.initials: S
authors.lastname: Muñoz Pérez
authors.forename: R
authors.initials: R
authors.lastname: Cobas
authors.forename: B R
authors.initials: BR
authors.lastname: Hansen
authors.forename: M
authors.initials: M
authors.lastname: Avdeev
authors.forename: W D
authors.initials: WD
authors.lastname: Hutchison
mesh_terms: D003460:Crystallization; D018360:Crystallography, X-Ray; D005708:Gallium / Q000737:chemistry*; D060328:Magnetic Phenomena; D059346:Magnets / Q000737:chemistry*; D008958:Models, Molecular; D033363:Neutron Diffraction; D033362:Powder Diffraction; D015204:Spectroscopy, Mossbauer; D013696:Temperature; D013932:Thulium / Q000737:chemistry*
chemical_list: D013932:Thulium; D005708:Gallium