Magnetic structures of HoBdSb compound

Abstract

Neutron diffraction measurements for two HoPdSb samples obtained by two different ways of preparation (samples 1 and 2) are presented. Neutron data above T N (Néel temperature) indicate that HoPdSb exists in two different crystalline phases: cubic MgAgAs-type ( F 4 3 m space group) and hexagonal LiGeGa-type ( P 6 3 mc space group). The weight percentages of these two phases are 75%-cubic, 25%-hexagonal for sample 1, 3%-cubic, 97%-hexagonal for sample 2. At low temperatures, the Ho magnetic moments in HoPdSb are ordered, whatever the crystal structure. For cubic HoPdSb, below T N = 2.7(2) K, a MnO-type antiferromagnetic structure is obtained, with Ho magnetic moments perpendicular to [1 1 1] direction and equal to 4.50(5) μ B at 1.5 K. For hexagonal HoPdSb, below T N = 3.8(2) K, a collinear antiferromagnetic structure is obtained, with propagation vector k = ( 1 2 0 0) , Ho magnetic moments parallel to c -axis and equal to 2.05(5) μ B at T = 1.5 K.