Mixed rare earth oxides derived from monazite sand as an inexpensive precursor material for room temperature magnetic refrigeration applications

作者：Arun B; Akshay V R; Mutta Geeta R; Venkatesh Ch; Vasundhara M^*

来源：Materials Research Bulletin, 2017, 94: 537-543.

DOI：10.1016/j.materresbull.2017.07.006

• Perovskite
• magnetocaloric
• rare earth oxides

An inexpensive perovskite type (REMIX)(0.67)Sr0.33MnO3 compound is synthesized via solid state method using mixed rare earth oxide precursor derived from monazite sand. Rietveld refinement of X-ray powder diffraction patterns confirms the compound is a mixture of rare earth manganites which is the major phase and CeO2 as the secondary phase. The compound shows a second order ferromagnetic to paramagnetic transition near room temperature and exhibits a magnetic entropy change (-Delta S-M) of 3.28 j kg(-1) K-1 with a relative cooling power (RCP) of 120j kg(-1) and an adiabatic temperature change (Delta T-ad) of 2.11 K at 310 K under 50 kOe magnetic field. The Debye temperature of the compound is found to be 543 K and room temperature thermal conductivity is 4.26 W m(-1) K-1. The temperature variation of electrical resistivity shows a metal to insulator transition around 180 K, which gets shifted towards higher temperature upon the application of magnetic field. The compound shows a large value of -Delta S-M and this work makes an endeavor to develop low-cost materials for the magnetic refrigeration applications near the room temperature.

• 出版日期2017-10