PREPARATION OF NI-FE/CU MULTILAYERS WITH LOW COERCIVITY AND GMR EFFECT BY ION-BEAM SPUTTERING

Multilayers composed of 30 [Ni-Fe/Cu] bilayers deposited on a 50-angstrom-thick Fe buffer layer were prepared by ion beam sputtering. The magnetoresistance (MR) ratio DELTArho/rho0 of the multilayers took high value at the Cu layer thickness delta(Cu) of 10, 20, and 32 angstrom for the multilayers with Ni-Fe layer thickness delta(Ni-Fe) of 10 angstrom. It was observed that (100) orientation of Ni-Fe and Cu crystallites were enhanced at delta(Cu) of 20 and 32 angstrom. The multilayered film with delta(Cu) of 10 angstrom exhibited DELTArho/rho0 as high as 12%. The multilayered film possessed good soft magnetic properties, and exhibited coercivity H(c) and relative permeability mu(r) of about 4 Oe and 800, respectively. The saturation magnetic field H(s) was about 300 Oe. DELTArho/rho0, H(c), and H(s) at delta(Cu) of 20 angstrom, i.e., at the ''second peak,'' were 6%, 10 Oe, and 25 Oe, respectively. The delta(Cu) dependence of DELTArho/rho0 seemed to be correspondent to that of the preferential orientation of the (100) plane. Ni-Fe/Cu multilayers with the same construction but without an Fe buffer layer did not reveal apparent (100) preferential orientation and did not exhibit DELTArho/rho0 as high as detectable. Then, DELTArho/rho0 was strongly dependent not only on interlayer thickness, such as delta(Cu) but also (100) crystallite orientation.