Development of SMA thin film deposited on buffer layer

The shape memory effect for TiNi to improve by using strain in the thin film deposited on a buffer layer (Nb, Mo, Ta, and W) has been investigated. First of all, the contact points on each surface between TiNi thin film and buffer layers (where the contact point is defined as atomic position difference for bonding between each atom on lattice axis in both surface of thin film and buffer layer) were calculated to obtain the mismatch rate under 1 %. Secondly, TiNi thin films on each buffer layers deposited by ECR sputter deposition method were evaluated by XRD and these strains in the films by changed lattice constants by the effect of buffer layer were also calculated from the sifted incident angles based on ICDD. As the result, the relationship between contact points and strained lattice constant in thin film calculated by using data based on XRD intensity data showed strong negative correlations and the contact points is effective to control the lattice constant of the thin films to give the strain into the thin film.