Magnetic Ordering of RAgSb2 Compounds

G. Andréa, F. Bouréea, M. Kolendab, B. Leśniewskac, A. Oleśc and A. Szytułab a Laboratoire Léon Brillouin (CEA-CNRS) CEN-Saclay, 91191 Gif-Sur-Yvette Cedex, France b Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Kraków, Poland c Department of Physics and Nuclear Techniques, Academy of Mining and Metallurgy, Reymonta 19, 30-059 Kraków, Poland

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The magnetic structures of the polycrystalline samples of RAgSb2 (R=Ce, Pr, Nd, Tb-Tm) are determined. All compounds crystallize in the tetragonal ZrCuSi2-type of crystal structure and except CeAgSb2 they are antiferromagnets with a Néel temperature of 11 K for R = Tb and 2 K for Tm. CeAgSb2 below TC=9.5 K is ferromagnet with the magnetic moment equal to 0.33μB and parallel to c-axis. In NdAgSb2 the sine modulated magnetic ordering described by the wave vector k = (0.5435,0,0) is observed. Below TN a collinear antiferromagnetic structure with the magnetic (a,a,2c) for R = Pr and (2a,a,c) for R = Tb, Dy, Ho, and Er is observed. For Ho-compound with an increase in temperature the coexistence of two structures is observed: commensurate collinear and incommensurate sine modulated. In TmAgSb2 the coexistence of the two phases is observed at T = 1.4 K. With an increase in temperature only the incommensurate phase stays.

DOI: 10.12693/APhysPolA.97.771 PACS numbers: 75.30.Cr, 75.30.Kz, 75.50.Ee