Pulsed laser deposition of NiMnGa thin films on silicon

Thin films of the magnetic shape-memory (MSM) material NiMnGa have been deposited on Si(100) substrates using pulsed laser deposition. The 200 -300-nm-thick films were prepared at substrate temperatures ranging from 450 degreesC to 650 degreesC and at different background Ar pressures. Large saturation magnetizations, up to 60% of the bulk value, were measured for the films. Only the films deposited in vacuum or at Ar pressures below 10(-3) mbar and at temperatures between 500 degreesC and 600 degreesC were ferromagnetic. The films are mainly crystallized in the austenitic phase and they have a smooth surface with a low droplet density (0.01 mum(-2)). The magnetization and surface quality are sufficient that the films could be utilized in the realization of thin-film MSM devices.