Magnetoresistivity in CoFe2O4-BaTiO3 composites produced by spark plasma sintering

Ceramic composites of (CoFe2O4)(x)-(BaTiO3)((1-x)) with x = 0.20, 0.25, and 0.30 have been synthesized by spark plasma sintering at 1000 degrees C under a uniaxial pressure of 75 MPa using commercially available nanopowders as starting materials. The composites reveal a negative magnetoresistivity effect of about -1% at room temperature. An enhancement was observed at lower temperatures, and an effect of -4.1% was found in the composite with x 0.30 at 150 K by applying an external magnetic field of 25 kOe. The temperature dependence of the resistivity indicates variable range hopping involved in charge transport. (C) 2011 American Institute of Physics. [doi:10.1063/1.3622584]