International Journal of Current Research, vol.5, no.3, pp.607-610, 2013 (Refereed Journals of Other Institutions)
Multilayer ultrathin films of Cr/Ni80Fe20/Cr/Ni80Fe20/Cr were grown on p-type Si substrate by magnetron sputtering deposition. Thickness dependencies of multilayer thin films were analyzed with impedance spectroscopy. The samples were characterized in a frequency range of 100k – 40M Hz under different DC bias voltages varying from 0 to 1 V. The dependence of relaxation time on the dielectric relaxation frequency was determined from the Cole-Cole plots for different thicknesses two ultrathin permalloy /Cr/ permalloy thin films. The values inferred from Cole-Cole plots suggest that this is a Debye-type dielectric relaxation process under DC bias and we propose that this result is due to the dipolar structure of the samples and the capacitive nature of the interfaces between adjacent layers.