Field-Dependent Electrical and Thermal Characterization of Cu/CoFe Multilayer for Giant Magnetoresistive (GMR) Head Applications

Giant Magnetoresistance (GMR) head technology is one of the latest advancement in hard disk drive (HDD) storage industry. The GMR head superlattice structure consists of alternating layers of extremely thin metallic ferromagnet and paramagnet films. A large decrease in the resistivity from antiparallel to parallel alignment of the film magnetizations can be observed, known as giant magnetoresistance (GMR) effect (Baibich et al., 1988; Binasch et al., 1989). The GMR effect is generally due to the spin dependent electron bulk and interfacial scattering in the GMR multilayer structures (Zhang et al., 1992). However, in order to understand the nature of the spin-dependent electron scattering mechanism responsible for the GMR effect, both electrical and thermal transport properties of such multilayer structures must be measured and understood. It is suggested that the thermal transport property measurements in GMR can be used to judge whether the scattering processes responsible for the GMR have elastic and/or inelastic components (Shi et al., 1996). Moreover, the GMR effect is anticipated to have a thermal counterpart, known as giant magnetothermal resistance (GMTR) effect in which the thermal conductivity shows a ‘giant’ change under magnetic field.