Some properties of La-deficient La0.54Ca0.32MnO3-δ
A La-deficient sample of La0.54Ca0.32MnO3-δ was prepared by the solid-state reaction method. The Curie temperature TC equals 300 K, which is significantly higher than those of the La1-xCaxMnO3-δ system. The magnetic-entropy change reaches a maximum value of -ΔSM ≅ 5.5 J/kg K at the Curie temperature upon a 5 T magnetic field variation. A saturation magnetic moment σS = 2.99 μB/f.u. at 5 K has been derived from the magnetization data. Values of 0.0230 and 0.441 for the oxygen deficiency δ and the ratio of Mn3+/Mn4+, respectively, have been determined. From our study, it is suggested that this compound is a suitable candidate for application as a working substance in magnetic refrigeration. © 2003 Elsevier Science B.V. All rights reserved.