Thickness dependence of structural and magnetic properties of electrodeposited Co2FeSn films

Abstract

Co2FeSn films have been electrochemically deposited on polycrystalline Cu substrates in potentiostatic mode. Processed films with thicknesses of 320 nm, 780 nm, and 1400 nm exhibited highly ordered L21 type crystal structure with saturation magnetizations of 1023.38 kA/m (5.08 ± 0.04 μB/f.u.), 1035.31 kA/m (5.14 ± 0.04 μB/f.u.) and 1044.34 kA/m (5.18 ± 0.04 μB/f.u.) at 5 K and 965.00 kA/m (4.79 ± 0.04 μB/f.u.), 967.75 kA/m (4.81 ± 0.04 μB/f.u.), and 1003.52 kA/m (4.97 ± 0.04 μB/f.u.) at 300 K, respectively. The soft ferromagnetic films possess coercivity of ∼ 15.92 kA/m (200 Oe) with a high effective anisotropy constant of ∼ 105 J/m3. Thermo-magnetization measurements yielded high Curie temperatures of 995 K, 1005 K, and 1123 K for films of thicknesses 320 nm, 780 nm, and 1400 nm, respectively. Tailoring the thickness from 320 to 1400 nm could be achieved by merely varying the electrodeposition time without appreciable departure from chemical stoichiometry or compromise in crystalline order or magnetic properties. This establishes a methodology to prepare high quality L21 ordered Co2FeSn films with a few hundred nanometers thickness by electrodeposition. Electrodeposited Co2FeSn films with high magnetic moment, high Keff value, and high Curie temperature are potential candidates for fabricating nanomagnetic devices.