Temperature dependence of magnetoresistance effect in Ag-Fe3O4 composites films

We have observed an anomalous magnetoreisistance effect in Agx-(Fe3O4)1-x composite films. A positive MR value is found at small values of x. As the temperature is decreased, the positive MR ratio becomes significantly larger and appears with a wider range of x. The thermal influence on magneto-transport behavior in Agx-(Fe3O4)1-x composite films confirms that the spin injection from Fe3O4 into Ag granules induces spin accumulation in Ag granules and thus impede the current causing a larger resistance under a field