Low-Temperature Magnetic and Magnetocaloric Properties of Manganese-Substituted Gd0.5Er0.5CrO3 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.

Structural, Optical, Magnetic, and Magnetocaloric Properties of Sn2Mn2O7 Pyrochlore

“…This value for the SMO compound is smaller than that for Fe 2 Mn 2 O 7 and Al 2 Mn 2 O 7 compounds. [ 21,22 ] The effective magnetic moment of the compound was determined experimentally in units of Bohr magneton () using the fitted Curie constant ( C ) value obtained from the following relation: [ 31 ] …”

“…On the basis of isothermal magnetization data, magnetic entropy change () can be evaluated by the following Maxwell equation: [ 31 ] …”

A brief review on rare-earth chromites: synthesis, properties and applications

“…The super-exchange mechanism of antiparallel arranged Cr 3+ -O-Cr 3+ results in the canted antiferromagnetic ordering of LaCrO 3 [180]. This magnetic response triggers the directional anisotropy termed as exchange bias (EB) and its presence is manifested by the shifting of the magnetic hysteresis loop as well as an increase in its coercivity in an external magnetic field [127]. Their dielectric constant usually reveals the typical response, wherein they decrease abruptly at lower frequencies and evolve to be constant at higher frequencies.…”