Synthesis, magnetic and magnetocaloric properties of transition element doped La.sub.0.67Ba.sub.0.33MnO.sub.3

Colossal magnetoresistance materials have demonstrated large changes in resistance in the presence of magnetic fields. In the current work, a group of such materials, with the compositional formula La.sub.0.67Ba.sub.0.33MnO.sub.3 and 10% Fe, Co, Ni, Zn doped La.sub.0.67Ba.sub.0.33MnO.sub.3 have been prepared by conventional solid-state method. Structural analysis has been carried out by X-Ray diffraction method followed by Rietveld analysis. Magnetic transition between ferromagnetism to paramagnetism has been observed from the magnetic characterizations. Parameters such as Curie temperature ([theta].sub.P) and effective magnetic moment ([micro].sub.eff) are obtained from susceptibility analysis subject to Curie-Weiss law. Furthermore, magnetocaloric nature of the samples is examined from the M-H isotherms. Using Maxwell's relations, isothermal entropy change, âS.sub.max are determined to check whether the prepared samples can be used for magnetic refrigeration around the room temperature.