Fe_(x)(SiO)_(1-x) thin films, with volume fraction x ranging from 0.04 to 0.6, have been prepared by coevaporation. Magnetization, resistivity, and magnetoresistance measurements show that the behavior of this composite is metallic like for x≥0.35. For 0.2≤x≤0.27, the confrontation of all measurements prove the existence of a tunneling giant magnetoresistance between ferromagnetic grains at T<300 K, where the mean radius of the grains is estimated to be about 1 nm.
展开▼
