Magnetic properties of Ni1−x−yCoxFey films deposited by polyol electroless process

Abstract

Electroless deposition using a nonaqueous, polyol process is carried out to produce nickel-rich Ni0.5Co0.5−xFex and cobalt-rich Co0.5Ni0.5−xFex (x=0, 0.1, 0.3, 0.5) ternary alloy films, and investigate the effect of incorporating iron on the morphology and magnetic properties of these two series of films. The plating solution used to deposit these films is prepared by mixing proportional volumes of equimolar metal salts suspended in ethylene glycol. Plating was performed by refluxing the nonaqueous solution at a temperature of 194 °C. The deposited films were characterized by electron microscopy, optical interferometry and X-ray diffraction. In the case of cobalt-rich films (Co0.5Ni0.5−xFex, x=0.0–0.5), a transition in the crystal structure from lower symmetric orthogonal to higher symmetric tetragonal or cubic structures was observed with increasing iron content. There was no such change for the nickel-rich films (Ni0.5Co0.5−xFex,x=0–0.5). The addition of iron was found to increase the surface roughness of both series of films. The magnetic measurements showed excellent soft-magnetic characteristics for as synthesized Co0.5Fe0.1Ni0.4 film with Ms, Hc, Ms⊥ and Hc⊥ values of 725.2 emu/cm3, 28 Oe, 205 emu/g and 176.5 Oe, respectively. The incorporation of iron was found to enhance the soft-magnetic characteristics of the otherwise weak magnetic Ni0.5Co0.5 film.