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Crystal and magnetic structures of R 2 Ni 1.78 In compounds ( R = Tb, Ho, Er and Tm)
Author(s) -
Baran Stanisław,
Deptuch Aleksandra,
Hoser Andreas,
Penc Bogusław,
Tyvanchuk Yuriy,
Szytuła Andrzej
Publication year - 2021
Publication title -
acta crystallographica section b
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.604
H-Index - 33
ISSN - 2052-5206
DOI - 10.1107/s2052520621008179
Subject(s) - antiferromagnetism , tetragonal crystal system , magnetic moment , magnetic structure , neutron diffraction , crystal structure , crystallography , physics , condensed matter physics , chemistry , magnetic field , magnetization , quantum mechanics
The crystal and magnetic structures in R 2 Ni 1.78 In ( R = Ho, Er and Tm) have been studied by neutron diffraction. The compounds crystallize in a tetragonal crystal structure of the Mo 2 FeB 2 type (space group P 4/ mbm ). At low temperatures, the magnetic moments, localized solely on the rare earth atoms, form antiferromagnetic structures described by the propagation vector k = [ k x , k x , ½], with k x equal to ¼ for R = Er and Tm or 0.3074 (4) for R = Ho. The magnetic moments are parallel to the c axis for R = Ho or lie within the (001) plane for R = Er and Tm. The obtained magnetic structures are discussed on the basis of symmetry analysis. The rare earth magnetic moments, determined from neutron diffraction data collected at 1.6 K, are 6.5 (1) μ B (Er) and 6.09 (4) μ B (Tm), while in the incommensurate modulated magnetic structure in Ho 2 Ni 1.78 In the amplitude of modulation of the Ho magnetic moment is 7.93 (8) μ B . All these values are smaller than those expected for the respective free R 3+ ions. A symmetry analysis of the magnetic structure in Tb 2 Ni 1.78 In is also included, as such information is missing from the original paper [Szytuła, Baran, Hoser, Kalychak, Penc & Tyvanchuk (2013). Acta Phys. Pol. A , 124 , 994–997]. In addition, the results of magnetometric measurements are reported for Tm 2 Ni 1.78 In. The compound shows antiferromagnetic ordering below the Néel temperature of 4.5 K. Its magnetic properties are found to originate from magnetic moments localized solely on the thulium atoms (the nickel atoms remain non‐magnetic in Tm 2 Ni 1.78 In). The reduction of rare earth magnetic moments in the ordered state in R 2 Ni 1.78 In ( R = Tb, Ho, Er and Tm) and the change in direction of the moments indicate the influence of the crystalline electric field (CEF) on the stability of the magnetic order in the investigated compounds.