Tunneling magnetoresistance effect of granular Co-Ta-O films sputtered under an oblique cathode arrangement

Tunneling magnetoresistance of granular Co-Ta-O films sputtered under an ob liquely arranged electrodes was investigated as a function of the film thic kness and the concentration of Co to Ta2O5. Formation of micro-scale struct ures such as corrugated surface elongating perpendicular to the incident io n-beam (thickness<50nm) and columnar structure inclined to the normal of th e film plane (thickness>50nm) were quite similar to vacuum evaporated films . As a result of these structures, the resistivity at zero held rho(0) and the resistivity change with field Delta rho became about 1 order of magnitu de larger compared to those of films sputtered under ordinary parallel elec trode arrangement.