Relevant GMR in as-deposited Co-Ag electrodeposits: Chronoamperometric preparation

Electrodeposited Co-Ag granular films were prepared by potentiostatic deposition from a chloride-based electrolyte. Different Co(II)/Ag(I) ratios were tested to study the influence of the composition bath on the magnetotranport properties. All as-deposited samples showed GMR effect because both longitudinal and transverse magnetoresistances were negative in the whole field range. GMR values up to 5.85% were measured at room temperature. Electrochemical and structural techniques (XRD, TEM, and electron diffraction) as well as magnetoresistance measurements confirmed the heterogeneity of the deposits with a size distribution from superparamagnetic to ferromagnetic particles. Fcc-Ag and a mixture of hcp-Co and fcc-Co were present in the coatings. An analysis of the magnetotransport properties based on the decomposition of the total magnetoresistance into its ferromagnetic and superparamagnetic contributions revealed a high superparamagnetic contribution in all samples. © 2010 American Chemical Society