The magnetic and electronic properties of REAgSb2 compounds.

• The susceptibility of the compounds with RE = Sm and Gd-Dy exhibits an upturn below T N. • Due to spin-flip, the metamagnetic transitions are observed in REAgSb 2 (RE = Pr, Gd-Ho) compounds. • ΔS max of CeAgSb 2 and PrAgSb 2 under the applied magnetic field of 6 T are 5.1 and 7.9 J.kg−1.K−1, respectively. • The variation in the DOS of REAgSb 2 compounds are dominated by the RE 4f bands. Magnetic properties and electronic structure of REAgSb 2 compounds (RE = La-Nd, Sm and Gd-Er) were investigated by experimental measurements on their polycrystalline samples combining with first-principles calculation. X-ray powder diffraction analysis shows that all compounds crystallize in a tetragonal HfCuSi 2 -type structure (Space group P 4/ nmm , No. 129, tP8). The results of magnetic measurements reveal that LaAgSb 2 is non-magnetic, CeAgSb 2 is ferromagnetic, and other compounds are antiferromagnetic. The magnetic ordering temperatures were obtained by d M /d T plots, which are distributed between 3.2 and 14.2 K. According to Curie-Weiss law, it was found that the effective magnetic moments of these compounds are close to rare earth trivalent ions in REAgSb 2. The metamagnetic transitions are observed for REAgSb 2 (RE = Pr, Gd-Ho) according to M−H curves at 2 K. The Arrott plots reveal that the magnetic phase transition type belongs to second-order phase transition for REAgSb 2 (RE = Ce, Pr). The maximum magnetic entropy changes of CeAgSb 2 and PrAgSb 2 are measured to be 5.1 and 7.9 J.kg−1.K−1, respectively. The electronic structures of REAgSb 2 compounds have been studied based on density functional theory. The electronic structures data of REAgSb 2 suggest that the DOS dispersions are close to the RE 4f electrons and there is a strong correlation between RE and Sb atoms. The hybridization between RE 4f and Sb 5p electrons gradually increases as a function of atomic number for REAgSb 2 (RE = Ce-Sm, Gd), while gradually decreases for the other compounds. [ABSTRACT FROM AUTHOR]