抄録
We studied the giant magnetoresistance (GMR) and related properties of (Fe, CO)-X-O (X=Y, Nd, Sm, Gd, Tb, Dy) films. The films were prepared by conventional rf sputtering of Fe, CO or Fe-Co, and X2O3 targets. The films seem to have a granular structure composed of nano-size metallic grains and thin oxide boundaries. The films exhibited superparamagnetic properties and high electrical resistivities of 104-106 μΩcm, and had negative and isotropic magnetoresistances at room temperature. The values of Δρ/ρ0 in Co-based films were larger than those of Fe-based films, and a GMR effect of 2.7% at 500 Oe was observed for Co51.0Sm10.7O38.3 The GMR effect film at room temperature. observed in the granular structure is attributed to spindependent tunneling conductance through a thin oxide layer between grains in the film.
