PULSED-LASER DEPOSITION OF NITI SHAPE-MEMORY EFFECT THIN-FILMS

We report for the first time on the pulsed laser deposition of NiTi sh ape-memory effect thin films. Using a NiTi bulk target with a 1:1 nomi nal stoichiometry, we deposited thin films (thickness approximate to 0 .6 mu m) on both Si(100) and Al2O3(100) substrates. We also produced f ree-standing NiTi films by deposition on KBr substrates and subsequent substrate removal by immersion in water. The presence of the solid-so lid phase transformation responsible for the shape memory effect has b een demonstrated through temperature-dependent X-ray diffraction and f our-probe resistance versus temperature measurements. On cooling the d eposited him, the austenite-martensite transformation was measured at around 195 K; on heating the film the reverse transformation was aroun d 250 K. Evidence of the shape-memory effect for freestanding films wa s obtained in a bending deformation-shape recovery experiment.