Evolution of magnetic and structural properties from Ag nanolayers to several microns Co-Ag deposits prepared by electrodeposition

The evolution of composition, morphology, magnetic properties and crystalline structure of Co-Ag electrodeposits from nanometric to micrometric thicknesses has been analyzed. Different substrates (Si/Ti/Ni, Si/Cr/Cu and glass/ITO) have been used to electrodeposit the Co-Ag system. The same trend was observed in all cases: after a first nanometric silver layer, cobalt was gradually incorporated till constant composition was attained. Moreover, a gradual variation of the magnetic response of the films from diamagnetism to superparamagnetism and then ferromagnetism was detected by increasing the deposition charge. fcc-Ag, hcp-Co and a metastable phase hcp-CoAg3 were present in Co-Ag micrometric deposits grown over Si/Ti/Ni from the very early deposition stages, these deposits showing coercivity values around 115 Oe. However, deposits of lower coercivities (around 50 Oe) were obtained over glass/ITO and Sill Cr/Cu substrates, these deposits being constituted by fcc-Ag and hcp-Co. (C) 2009 Elsevier B.V. All rights reserved.