MATERIALS 3 , 024406 ( 2019 ) From Tb 3 Ni 2 to Tb 3 CoNi : The interplay between chemistry , structure , and magnetism

Formation, crystal structure, and macroscopic and microscopic magnetism of the binary Tb3Ni2 and derivative pseudobinary Tb3CoxNi2−x phases have been investigated using an array of experimental methods. While Tb3Ni2 crystallizes in the monoclinic Dy3Ni2 structure type (mS20, C2/m), the substitution of Co for Ni results in a structural transition into the rhombohedral Er3Ni2 type (hR45, R ̄3h) at x(Co)≈0.34 and beyond in the Tb3CoxNi2−x system. In both the monoclinic and rhombohedral phases, the addition of Co leads to an anisotropic change of lattice parameters and unexpected reduction of the cell volume. Measurements of bulk properties reveal that these compounds order ferrimagnetically or ferromagnetically at about 100 K. Complex noncollinear ferromagnetic ordering in the Tb sublattices is weakly dependent on composition. For x > 0.34 the long-range magnetic ordering leads to a strong anisotropic magnetostriction accompanied by a symmetry reduction from rhombohedral to triclinic. Disciplines Condensed Matter Physics | Materials Science and Engineering Authors Clemens Ritter, Alessia Provino, Francois Fauth, Sudesh K. Dhar, Vitalij K. Pecharsky, and Pietro Manfrinetti This article is available at Iowa State University Digital Repository: https://lib.dr.iastate.edu/ameslab_manuscripts/318 PHYSICAL REVIEW MATERIALS 3, 024406 (2019) From Tb3Ni2 to Tb3CoNi: The interplay between chemistry, structure, and magnetism Clemens Ritter,1 Alessia Provino,2,3,4 Francois Fauth,5 Sudesh K. Dhar,6 Vitalij K. Pecharsky,3,7 and Pietro Manfrinetti2,3,4,* 1Institut Laue-Langevin, BP 156, 38042 Grenoble, France 2Department of Chemistry, University of Genova, Via Dodecaneso 31, 16146 Genova, Italy 3The Ames Laboratory, US Department of Energy, Iowa State University, Ames, Iowa 50011, USA 4Institute SPIN-CNR, Corso Perrone 24, 16152 Genova, Italy 5CELLS-ALBA Synchrotron, Carrer de la Llum 2-26, 08290 Cerdanyola del Vallès, Barcelona, Spain 6Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India 7Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011, USA (Received 13 December 2018; revised manuscript received 25 January 2019; published 20 February 2019) Formation, crystal structure, and macroscopic and microscopic magnetism of the binary Tb3Ni2 and derivative pseudobinary Tb3CoxNi2-x phases have been investigated using an array of experimental methods. While Tb3Ni2 crystallizes in the monoclinic Dy3Ni2 structure type (mS20, C2/m), the substitution of Co for Ni results in a structural transition into the rhombohedral Er3Ni2 type (hR45, R3̄h) at x(Co) ≈ 0.34 and beyond in the Tb3CoxNi2-x system. In both the monoclinic and rhombohedral phases, the addition of Co leads to an anisotropic change of lattice parameters and unexpected reduction of the cell volume. Measurements of bulk properties reveal that these compounds order ferrimagnetically or ferromagnetically at about 100 K. Complex noncollinear ferromagnetic ordering in the Tb sublattices is weakly dependent on composition. For x > 0.34 the long-range magnetic ordering leads to a strong anisotropic magnetostriction accompanied by a symmetry reduction from rhombohedral to triclinic. DOI: 10.1103/PhysRevMaterials.3.024406