Colossal magnetoresistance in the double perovskite oxide La2CoMnO6

Polycrystalline sample of La2CoMnO6 has been synthesized by sol-gel technique. The powder x-ray diffraction data confirm the single phase nature of the sample. This compound has monoclinic crystal structure (space group P2(1)/n) at room temperature. The temperature dependence of magnetization in low field shows considerable variation between zero-field-cooled and field-cooled magnetization curve below similar to 210 K (TC) and it follows Curie-Weiss law in the paramagnetic region. The hysteresis loop at 5 K indicates a coercive field of similar to 6 kOe and remnant magnetization of similar to 2.32 mu(B)/f.u. The temperature dependence of the resistivity data shows semiconductorlike behavior in the temperature range of 5-350 K and follows variable range hopping conduction mechanism in the temperature range 215-350 K. Acolossal magnetoresistance of similar to 80% is observed at 5 K in an applied field of 80 kOe and MR has a negative sign. (C) 2010 American Institute of Physics. [doi:10.1063/1.3350907]