Co/Cu multilayers with reduced magnetoresistive hysteresis

Practical applications of Co/Cu multilayers (MLs) require copper thicknesses either approximate to 9 Angstrom or approximate to 20 Angstrom corresponding to the first or second antiferromagnetic maximum (AFM). The first AFM has much smaller magnetoresistive hysteresis than the second, but also has lower sensitivity. We discuss application of these MLs when low hysteresis is required. For the first AFM we may improve the sensitivity while retaining low hysteresis by increasing the cobalt thickness to 30-40 Angstrom. At the second AFM we can reduce the magnetoresistive hysteresis by reducing the cobalt thickness to similar to 3 Angstrom. A particularly attractive combination of high sensitivity and low hysteresis is obtained at the second AFM by alternating such very thin Co layers with 15 Angstrom thick Co layers.