Magnetic properties and magnetocaloric effect in layered NdMn1.7V0.3Si2

Abstract

Magnetocaloric effect (MCE) around TC ~ 18 K is found in NdMn1.7V0.3Si2 associated with first order magnetic transition from antiferromagnetic to ferromagnetic. The magnetic entropy change –DSM= 12 Jkg/K and adiabatic temperature change DTad=4.7 K have been determined using magnetization and specific heat measurement. Neutron investigations indicate that magnetostructural coupling plays a critical role on the magnetocaloric effect. The study of MCE has become an interesting area of research in the field of magnetic materials as magnetic refrigerant especially in first order transition material [1]. NdMn1.7V0.3Si2 was be selected for our investigation because the ferromagnetic (FM) ordering of the Nd sub-lattice offer scope for simultaneous FM ordering of the Mn sub-lattice [2]. Regarding to the large difference in the atomic radius of Mn (1.24Å) and V (1.34Å), we expect that replacement of Mn byV in NdMn2Si2 will significantly modify the magneticstates of both the Nd and Mn sub-lattices. Neutron diffraction study indicates that, above TC, Nd sublattice does not order but Mn sublattice orders antiferromagnetic (AFil-type) with full moment without anycanting. We observe that spontaneous magnetization decreases with V concentration - indicating that replacement of Mn by V dilutes magnetism in NdMn2-xVxSi2 compounds due to factthat V is nonmagnetic element.