Kinetic interface roughening and magneto resistance of sputter-deposited Fe/Ni75B25 multilayers

The roughening of interfaces as a function of layer thickness and magneto transport properties have been investigated on sputter-deposited Fe/Ni75B25 multilayer films. X-ray reflectivity data were recorded for Ni75B25(72 nm) film and for [Fe(2 nm)/ Ni75B25(2 nm)]16 and [Fe(4 nm)/Ni75B25(4 nm)]8 multilayer films. A power law dependence of the interfacial width of growing Fe/Ni75B25 interfaces was observed. The resulting growth exponents b were found to be in the range of 0.55–0.58 in the initial growth stage of the multilayer with lower Fe/Ni75B25 repetition thickness and at approximately 0.34 for multilayer with higher repetition thickness. The growth exponents were compared with theoretical calculations. High resolution electron microscopy revealed the columnar growth of the Fe/Ni75B25 multilayer. Additionally, an increase of magnetoresistance was observed by the multilayering of Ni75B25 films with Fe interlayers.