The pH Dependence of Magnetoresistance in Cu-Co Alloy Films Formed by Electrodeposition

I. H. Karahan；Ö. F. Bakkaloglu；M. Bedir

Chinese Journal of Physics

45卷4期（2007 / 08 / 01）

458 - 465

英文

Thin films of Cu(subscript 1-x)Co(subscript x)were electrochemically deposited onto aluminum substrates in a single sulfate bath. The GMR effect was investigated in the temperature range 20 to 300 K and in the magnetic field range 0 to 12 kOe. The bath pH values were selected as 5.25, 5.5, 5.75, 6, and 6.25. The compositions of the electrodeposited Cu(subscript 1-x)Co(subscript x)films were determined to be x=27.7, 27.4, 28.5, 37.9, and 28.4, respectively, by an atomic absorption spectrometer and an energy dispersive X-ray spectrometer. The crystal structure was FCC-Cu for all films, but a shift in the direction lines was observed with increasing Co content. All films showed a negative magnetoresistance (MR) effect. The maximum MR ratio at a magnetic field of 8.5 kOe was 1% in the pH=6 film at room temperature and 3.3% in the pH=6 film at 20 K. It was found that the composition, structure, and magnetoresistive (GMR) behaviour of the thin films exhibit a strong dependence on the pH values of the bath electrolyte.