EFFECT OF ULTRA-CLEAN SPUTTERING ON MAGNETORESISTANCE AND THERMAL-STABILITY OF MAGNETORESISTANCE IN SPIN-VALVES

The influence of the base pressure (8.6 x 10(-10)-1.3 x 10(-7) Torr) i n the sputtering chamber just before the deposition on the magnetoresi stance (MR) ratios and the thermal stability of the MR ratios in spin- valves (SVs) was studied, using purified sputtering Ar gas (impurity l evel less than 1 ppb). The resistivity rho in the SVs decreased and as a result, the MR ratio increased with decreasing base pressure. Also, the thermal stability of the MR ratio was improved with decreasing ba se pressure. The increase of grain size in the SVs fabricated under lo w base pressures bears a close relationship to the MR ratios and the t hermal stability of the MR ratios.