Magnetic, transport, and magnetocaloric properties of double perovskite oxide LaCaMnCoO6

Magnetic, magnetoresistive, and magnetocaloric properties of a novel double perovskite oxide, namely, LaCaMnCoO6 have been studied. Polycrystalline sample of LaCaMnCoO6 has been synthesized by sol-gel technique. It has cubic crystal structure (space group Fm (3) over barm) at room temperature. The temperature variation in magnetization reveals a steep increase in magnetization around 168 K (T-C). The magnetization does not even saturate at 5 K and a magnetic moment of 0.7 mu(B)/f.u. is obtained at 5 K in an applied field of 50 kOe. The electrical resistivity measurement indicates that the material is semiconducting-like in the temperature range of similar to 300-50 K and below similar to 50 K the sample becomes insulating. A maximum magnetoresistance (MR) of about 8% is found at 200 K in an applied field of 7 T and MR has a negative sign. The magnetocaloric effect is calculated from the magnetization versus temperature data and a maximum magnetic entropy change of 3.1 J/kg K for a field change of 11 kOe is obtained near T-C. Thus a moderate magnetocaloric effect is achieved in rather low magnetic fields. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3059592]