Structure, magnetic properties and thermal expansion of Mn3PtNx (0 ≤ x ≤ 1.0) compounds

Abstract

In this work, Mn3PtN[Formula: see text] (x = 0, 0.25, 0.5, 0.75 and 1.0) compounds were prepared by solid state reaction method. The structure, magnetic properties and thermal expansion behaviors of Mn3PtN[Formula: see text] compounds with different nitrogen content were systematically investigated. Mn3PtN has typical antiperovskite cubic structure with space group Pm-3m (221). With decreasing nitrogen content, the crystal structure changes to hexagonal with space group P63/mmc when the value of x decreases to x = 0.25, and then back to cubic with Fm3m at x = 0. All of the obtained Mn3PtN[Formula: see text] compound exhibit the magnetic transition from antiferromagnetic (AFM) to paramagnetic (PM). Moreover, another transition from AFM1 to AFM2 at lower temperature was also observed in Mn3Pt. The experimental results indicate that the magnetic transition induced abnormal thermal expansion behavior in Mn3PtN[Formula: see text]. Especially, a typical giant thermal expansion behavior of about [Formula: see text]8‰ volume change arising from the magneto-volume effect at 411 K is observed in Mn3Pt compound. The obtained results imply that this kind of compounds is a strong lattice–spin correlation system.