Low-Temperature Magnetic and Magnetocaloric Properties of Manganese-Substituted Gd_0.5Er_0.5CrO₃ Orthochromites

Abstract

Rare-earth chromites have been envisioned to replace gas-based refrigeration technology because of their promising magnetocaloric properties at low temperatures, especially in the liquid helium temperature range. Here, we report the low-temperature magnetic and magnetocaloric properties of Gd0.5Er0.5Cr1−xMnxO3 (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5) rare-earth orthochromites. The Néel transition temperature (TN) was suppressed from 144 K for Gd0.5Er0.5CrO3 to 66 K for the Gd0.5Er0.5Cr0.5Mn0.5O3 compound. Furthermore, magnetization reversal was observed in the magnetization versus temperature behavior of the Gd0.5Er0.5Cr0.6Mn0.4O3 and Gd0.5Er0.5Cr0.5Mn0.5O3 compounds at 100 Oe applied magnetic field. The magnetic entropy change (−∆S) value varied from 16.74 J/kg-K to 7.46 J/kg-K, whereas the relative cooling power (RCP) ranged from 375.94 J/kg to 220.22 J/kg with a Mn ion concentration at 5 T field and around 7.5 K temperature. The experimental results were substantiated by a theoretical model. The present values of the magnetocaloric effect are higher than those of many undoped chromites, manganites and molecular magnets in the liquid helium temperature range.

Keywords

• rare-earth orthochromites
• magnetization reversal
• magnetocaloric effect