Microstructure and Composition Design of Magnetic Ni-Mn-Sn Co-sputter Deposited Films

In this work, we study the effect of the substrate temperature (ST) during sputter-deposition as well as co-sputtering deposition on the fabrication of nanostructured Ni-Mn-Sn thin films. Sputtered films show Mn losses of around 10 at.% while the average grain size (<d>) increased from 30 nm to 105 nm with the increasing of ST. Mn losses compensation is proposed by co-sputtered deposition. With such a purpose a variable electrical power was applied to the radio frequency (RF) Mn cathode. By increasing the electrical power applied to the RF Mn cathode both Mn and Ni contents approach to the targeted nominal composition Ni:Mn:Sn = 50:37:13. Elemental chemical composition analyses show that the composition varied between Ni61.5Mn26.2Sn12.3 and Ni54.6Mn30.5Sn14.9 when the applied RF-power increased from 0 W to 30 W.