Thickness and pore size dependence of coercivity for nanonetwork of iron produced by template synthesis

Abstract

In this article we have studied thickness and pore size dependence of coercivity in iron films over the thickness range 1.875–45 nm at which Néel-type domain wall dominates. Nanonetwork of iron films were sputter deposited on commercial nanochannel alumina templates with nominal pore diameters of 20, 100, and 200 nm. Continuous films deposited on conventional glass substrates have also been studied in order to understand the effect of porosity on an otherwise nonporous film. While nanonetworks showed expected higher coercivity values than their continuous counterpart, it was found that the coercivity for nanonetworks was influenced by the thickness and the effective pore diameter of the deposited iron layer. Coercivity for conventional films on glass followed an inverse power law. For nanonetworks, thickness dependence of coercivity was complex and showed convolutions. An empirical thickness dependence of coercivity is proposed to explain the behavior of the thickness-varying coercivity for the nanonetworks.