Magnetic Characterization of Electrodeposited Pt1-xNix Alloy Films: Influence of Deposition Potential and the Presence of Boric Acid

Pt1-xNix (x = 0.25 to 0.92) thin films were examined for possible application as magnetic thermometers. The alloys were prepared by potentiostatic electrodeposition from aqueous chloride-based solutions in the presence and absence of 0.5 mol dm(-3) B(OH)(3). Alloy composition was controlled by the deposition potential with the Ni concentration increasing towards more reducing potentials. Films with x > 0.45 were ferromagnetic with the magnetization at 300 K increasing with nickel content. Magnetization vs temperature (M vs T) at 8 kA m(-1) (100 Oe) showed an increase in the Curie temperature from less than 200 K to above 400 K for the alloys investigated. For films deposited at potentials >-0.6 V vs the saturated calomel electrode (SCE), boric acid had negligible effect on the magnetization at the maximum applied field in M vs H measurements. In contrast, for depositions at more reducing potentials <-0.6 V vs SCE the presence of boric acid resulted in diminished magnetization. This effect was attributed to elevated incorporation of oxygen (up to similar to 4 atomic %), along with boron incorporation of about 400 mu mol mol(-1).

Automated summary

Pt1-xNix alloy thin films have potential applications as magnetic thermometers, with higher nickel content resulting in higher Curie temperatures. The presence of boric acid has negligible effect on the magnetization of films deposited at higher potentials, but reduces magnetization for films deposited at lower potentials.