Hysteresis reduction in NiFeCo/Cu multilayers exhibiting large low-field giant magnetoresistance

Abstract

Giant magnetoresistance (GMR) has been observed in Ni,,Fe,,Co,$Cu multilayered uniaxial magnetic thin films prepared by dc magnetron sputtering. Both easy and hard axis loops saturate at very low applied fields. The MR ratio reaches -80% of its saturation value in less than 30 Oe. A maximum MR ratio of -10% has been observed in the as-deposited state in a structure containing only ten bilayers. Typical hysteresis values for magnetoresistance loops are -4 Oe in the as-deposited state. A gradual decrease of this hysteresis has been observed with annealing. An increase in the saturation field is also observed with annealing. Short-term annealing increases the magnitude of the magnetoresistance ratio; prolonged annealing causes a decrease. A field sensitivity of about 0.3% per Oe has been observed and dc magnetoresistance minor loops exhibit no measurable decrease in sensitivity.

Atomistic simulations of the vapor deposition of Ni/Cu/Ni multilayers: The effects of adatom incident energy

“…This giant magnetoresistive ͑GMR͒ effect was first discovered in Fe/Cr sandwiches in 1988, 1,2 but many material systems have since been found to exhibit the effect. Frequently studied examples include Co/Cu/Co, [7][8][9][10][11][12][13][14][15][16][17][18][19][20] NiFe͑Co͒/Cu/NiFe͑Co͒, [21][22][23][24] and NiCo/Cu/ NiCo systems. 25 The GMR effect is a result of spindependent electron scattering.…”

Giant magnetoresistance multilayers of high thermal stability with thicker magnetic layers

“…1,2 The poor thermal stability of these structures has, however, been a critical issue in our earlier work, 2 as well as in that of other groups. 3 Hightemperature anneal causes serious degradation of the GMR magnitude and field sensitivity.…”

Buffer effect on GMR in thin Co/Cu multilayers

“…poor [6,10] or strong [11] (1 1 1) texture. It was shown that high GMR is correlated to low interfacial roughness in polycrystalline Co/Cu(2 0 0) and Co/Cu(1 1 1) MLs [7][8][9] in contrast with the results obtained for epitaxially deposited Co/Cu(1 1 1) by Egelhoff and Kief [12].…”