Unimorph cantilevers are made from 0.5BaTiO(3)-0.5Sm(2)O(3) (BTO-SmO) self-assembled vertical heteroepitaxial nanocomposite thin films, grown by PLD on (001) SrTiO3 single crystal substrates. The films remain piezoelectric up to at least 250 degrees C without losing any actuation. The longitudinal piezoelectric coefficient, d(33), is approximate to 45 to 50 pm V-1 measured from room temperature to 250 degrees C. The transverse piezoelectric coefficient, d(31), a key parameter of actuator performance, exceeds PZT (Pb1-xZrxTiO3) films at >200 pm V-1. Since the d(31) coefficient was found to be positive, this opens up exciting new applications opportunities. The possible reasons for d(31) > 0 are discussed in the light of 3D strain control in the nanocomposites.