Structural, magnetic, magnetocaloric and specific heat investigations on Mn doped PrCrO₃orthochromites

Abstract

We have synthesized PrCr_0.85Mn_0.15O₃ (PCMO) chromite and investigated the influence of manganese (Mn) doping at Cr-sites on the structural, magnetic, magnetocaloric and thermal properties of PrCrO₃ compound. No structural transition was observed with Mn substitution and the doped compound crystallized into distorted orthorhombic structure with Pnma space group which was confirmed by Rietveld refinement of x-ray powder diffraction patterns. Neel temperature, noticed at 168 K from the temperature variation of magnetization, smaller than that reported for PrCrO₃, indicated the influence of Mn³⁺ substitution in decreasing the antiferromagnetic ordering. Magnetization was almost eight times higher than that reported for undoped sample. Magnetocaloric effect measured via the magnetic entropy change and relative cooling power demonstrated significant values in the temperature range 10-20 K. The values of magnetic entropy change are much superior to that reported for other polycrystalline orthochromites and even at smaller applied field strength. The material exhibited second order magnetic phase transition. The Debye temperature and the density of states at Fermi level were also calculated. The overall results make PrCr_0.85Mn_0.15O₃ chromite a potential candidate to replace the existing materials for low temperature magnetic refrigeration.