Giant magnetoresistance and remanence in granular CoCu codeposited films

We present experimental magnetoresistance, magnetization, and remanence dat a for CoCu granular films obtained by electron beam codeposition, subsequen tly submitted to a thermal treatment. The magnetization measurements show c oexistence of superparamagnetic and ferromagnetic (or blocked superparamagn etic) Co grains. By modeling the experimental magnetization curves, the dis tribution function of the superparamagnetic particle size, the volume fract ion of the blocked part of the Co particles, and their saturation magnetiza tion are obtained. delta M plots are constructed using the remanence curves . A correlation between the changes of the delta M parameters and those of the giant magnetoresistance, caused by the annealing, is discussed. (C) 199 8 American Institute of Physics. [S0021-8979(98)46811-7].