Effect of the bath pH on the electrodeposition of nanocrystalline Pd–Co alloys and their magnetic properties

First order reversal curve analysis of nanocrystalline Pd80Co20 alloy films

“…Previously published SEM micrographs of our PdCo films obtained with plating baths at pH values of 5.5 and 6.5 displayed crystallites with dendritic morphology and arranged on the substrate plane with random orientation [14]. However, when the pH of the plating bath was increased to 7.5 or 8.5, the morphology of the crystallites changed to reveal cauliflower-like shapes.…”

“…The coefficient of thermal expansion of the brass substrate (˛b rass ≈ 20 × 10 −6 K −1 ) was close to that of the PdCo film (˛P d ≈ 12 × 10 −6 K −1 ; based on the assumption that the coefficient of the alloy was similar to that of pure Pd), and hence no appreciable stresses would be expected to originate from the thermal expansion of the samples. It is likely, therefore, that the lattice strain observed was associated with the residual stress resulting from the use of a chloride plating bath and from the large numbers of nuclei formed at the high current densities applied [14]. The highest residual stress was detected in the film deposited under conditions of highest H + concentration (i.e.…”

“…The PdCo alloy films studied were produced by electrodeposition in the galvanostatic mode onto commercial grade brass substrate using a previously described method [14]. A Kraft Dynatronix (Amery, WI, USA) model DPR 20-5-10 power source was employed to provide a constant current equal to 1 A, and films with enhanced magnetic characteristics, including coercivity and saturation magnetization [18], were prepared with an electrical current density of 250 mA/cm 2 and an electrical charge of 100 C for each deposit.…”

“…It has been recently demonstrated that the mean grain size of electrodeposits of PdCo alloy films may be controlled, without substantial changes in alloy composition, by variation of the pH of the electrodeposition bath [14]. Effectively, isotropic nanostructured films of composition Pd 80 Co 20 and mean grain sizes in the range 18-23 nm were obtained by galvanostatic electrodeposition from a chloride plating bath of pH between 5.5 and 8.5.…”

Electrochemical synthesis of magnetic nanowires with controlled geometry and magnetic anisotropy

“…The alloying of FTMs with palladium (Pd) can make Pd in ferromagnetic even with additions of FTMs as little as 0.1 at.% (in the case of Co; Nagle et al, 1962;Noce et al, 2006;Noce et al, 2007). Furthermore, FTM/Pd-based alloys exhibit interesting magnetic and physicochemical properties that are of special interest in several applications.…”