Magnetic Properties of Electrodeposited Cobalt-Platinum (CoPt) and Cobalt-Platinum-Phosphide (CoPtP) Thin Films

Abstract

CoPt and CoPtP thin films were synthesized using direct current (DC) aqueous electrodeposition from weak alkaline solutions. The basic plating solutions of binary CoPt thin films consisted of cobalt pyrophosphate [Co2P2O7] and chloroplatinic acid [H2PtCl6]. Various amounts of sodium hypophosphite [NaH2PO2] was added to deposit ternary CoPtP thin films. The film composition was adjusted by varying the several electrodeposition parameters including electrolyte composition, solution pH, and current density and correlated to their microstructure and magnetic property (i.e. coercivity and squareness). For the binary CoPt thin films, the maximum coercivities [in-plane coercivity (Hc,//) = ∼1,600 Oe, and perpendicular coercivity (Hc,⊥) = ∼2,500 Oe] were obtained from electrolytes containing 0.01 M H2PtCl6 + 0.04 M Co2P2O7 at current density (CD) of 7.5 mA cm−2. In the case of ternary CoPtP electrodeposits, the maximum coercivities (Hc,// = ∼2,600 Oe, and Hc,⊥ = ∼3,800 Oe) were achieved from baths containing 0.015 M H2PtCl6, 0.07 M Co2P2O7, 0.8 M NaH2PO2 at CD of 7.5 mA cm−2 and solution pH 9. It was suggested that microstructure and magnetic properties are affected not only by the type of substrate but also by chemical compositions and electrodeposition conditions.

Improvement of the Electrocatalytic Properties for the Methanol Oxidation Reaction (MOR) of the CoPt Alloy

“…The Co is also known as an oxophilic metal in the binary catalysts and has the advantage of being a cheap metal, leading to a decrease in the catalyst price. The CoPt alloys can be synthesized by several routes, among which we can mention the chemical reduction, electrochemical deposition or micellar technique [26][27][28][29][30][31].…”