Spin valves exchange biased by Co/Ru/Co synthetic antiferromagnets

Spin valves exchange biased by a Co/Ru/Co synthetic antiferromagnet were fabricated and characterized. Room temperature measurements show giant-magnetoresistance ratios above 5% and that fields in excess of 5000 Oe are needed to saturate the synthetic antiferromagnet. The saturation field of the synthetic antiferromagnet is higher than 3000 Oe at 250 degrees C, which yields the possibility of observing the spin valve effect at very high temperatures. The transfer curve of the patterned structure shows a much weaker magnetostatic coupling than that observed in standard spin valves of identical dimensions. This is a consequence of the particular magnetic configuration of the synthetic antiferromagnet, which promotes an almost vanishing magnetostatic field. (C) 1998 American Institute of Physics. [S0021-8979(98)03107-7].