Magnetic Properties and Structural Study of Ni-Co/Cu Multilayers Prepared by Electrodeposition Method

Abstract

Ni-Co/Cu multilayers have been grown by electrodeposition method from a single electrolyte (based on Ni(SO4).6H2O, Co(SO4).7H2O, Cu(SO4) and H3BO3) using galvanostatic control on titanium sublayers. The X-ray diffraction (XRD) patterns confirmed the multilayered structure with the nanometer thicknesses. Also, electron diffraction x-ray (EDX) analysis confirmed the purity of deposited samples. The morphology of the samples was estimated by scanning electron microscope (SEM). Magnetoresistance (MR) measurements were carried out at room temperature for the Ni-Co/Cu multilayers by measuring the resistivity in a magnetic fields varying between ±6kOe as a function of the Ni-Co and Cu layer thicknesses; (1 dCu(nm) 4 and 3 dNi-Cu(nm) 5). The Maximum value of giant magnetoresistance (GMR) was obtained when the Ni-Co and Cu thicknesses were 4.0nm and 4.0nm respectively. The hysteresis loop of the samples at room temperature was studied using an alternating gradient force magnetometer (AGFM). Finally, the temperature dependence of magnetization for Ni-Co/Cu multilayers; (dNi-Cu(4nm)/dCu(2nm) and dNi-Cu(3nm)/dCu(3nm)) measured by Faraday balance and decreasing the magnetization with increasing the temperature discussed according to electron scattering due to spin fluctuation.