SEM, XPS Studies, and Magnetoresistance Properties of Co, Ni, Co–N, and Ni–N Thin Films Prepared by Electrodeposition

Abstract

The effect was investigated of nitrogen impurities on the morphology and magnetoresistance properties of Co–N and Ni–N thin films. The films were electroplated onto aluminum substrates, at room temperature, using the same electrodeposition parameters (pH = 3 and temperature 30 ∘C) for all experiments. The films were compared with similar samples obtained in the absences of nitrogen impurities. Scanning electron microscopy, X-ray photoelectron spectroscopy, and magnetoresistance measurements were utilized to characterize the studied films. The presence of nitrogen in the electrodeposited films have a significant influence on the morphology and magnetoresistance of electrodeposited films. Incorporation of a small amount of nitrogen into electrodeposited films increases the magnetoresistance up to 0.21 % for Co–N thin films and respectively 0.65 % in the case of Ni–N films. We suppose that the shape of the magnetoresistance curves is influenced by the interaction between the magnetic moment of the neighboring Co or Ni grains (with ferromagnetic behavior) separated by the nonmagnetic regions. Interfacial complexities of a ferromagnetic metal/oxide interface in studied thin films could force the interfacial spins to align ferromagnetically or antiferromagnetically. They could be useful for technological applications in electronics.