화학공학소재연구정보센터
Materials Chemistry and Physics, Vol.139, No.2-3, 629-633, 2013
Rapid synthesis of La0.85Na0.15MnO3 by spark plasma sintering: Magnetic behavior and magnetocaloric properties
The La0.85Na0.15MnO3 perovskite has been synthesized in polycrystalline form using the Spark Plasma Sintering technique (SPS). The in-situ reaction proceeds in a few minutes at 800 degrees C under 50 MPa with the very high heating rate of 100 degrees C min(-1). Rietveld refinement of the X-ray diffraction patterns indicates that our sample is of pure single phase rhombohedral structure (R (3) over barc symmetry). Paramagnetic-ferromagnetic phase transition at T-C = 310 K is observed for our studied sample. Magnetic entropy change, vertical bar Delta S-M vertical bar, deduced from isothermal magnetization curves, is about 2.42 J kg K-1 in a magnetic applied field change of 5 T. Although this value is modest, the magnetocaloric effect extends over a large temperature range leading to an important value of the relative cooling power (RCP). The RCP value at 5 T reaches 316.6 J kg(-1). This value corresponds to about 77% of that observed in pure Gd. (C) 2013 Elsevier B.V. All rights reserved.