Pulsed laser deposition of NiTi shape memory effect thin films

We report for the first time on the pulsed laser deposition of NiTi shape-memory effect thin films. Using a NiTi bulk target with a 1:1 nominal stoichiometry, we deposited thin films (thickness approximate to 0.6 mu m) on both Si(100) and Al2O3(100) substrates. We also produced free-standing NiTi films by deposition on KBr substrates and subsequent substrate removal by immersion in water. The presence of the solid-solid phase transformation responsible for the shape memory effect has been demonstrated through temperature-dependent X-ray diffraction and four-probe resistance versus temperature measurements. On cooling the deposited him, the austenite-martensite transformation was measured at around 195 K; on heating the film the reverse transformation was around 250 K. Evidence of the shape-memory effect for freestanding films was obtained in a bending deformation-shape recovery experiment.