Structural and magnetocaloric properties of Gd2-xMnxO3 nanoparticles

Magnetic cooling is considered to be an important component of future green refrigeration. On this subject, rare earth oxides (RE2O3) are seen as a promising class of magnetic materials for low-temperature magnetic cooling technology. In this work, we report the influence of Mn substitution on the structural, magnetic and magneto-caloric characteristics of Gd2O3 powders synthesized by sol-gel route. Structural analysis using Rietveld refinement technique confirmed the cubic-bixbyite structure with the Ia3 space group. The lattice parameter slightly decreases with the Mn doping degree. Temperature dependent magnetization measurements demon-strated a paramagnetic behavior sustained in Gd2-xMnxO3 in the whole temperature range of 2-400 K and the presence of weak antiferromagnetic interactions at low temperature (<= 2K). The measured hysteresis loops are linear and completely reversible (2 K), which is typical for paramagnetic system and suitable for cryogenics magnetic refrigeration. The variation of the magnetic entropy was measured indirectly using the Maxwell approach with increasing magnetic field.