A method of growing KTa.sub.x Nb.sub.1-x O.sub.3 by pulsed laser evaporation. In order to compensate for the volatile K, two targets are prepared, one of sintered oxide powder having K, Ta, and Nb in amounts stoichiometric to KTa.sub.x Nb.sub.1-x O.sub.3 and the other of melt-grown KNO.sub.3. The method can also be used to form other complex materials having volatile components using a variety of sputtering growth techniques. The two targets are mounted on a rotating target holder and are alternately ablated by the laser beam. The KNO.sub.3 provides excess K, thus allowing the growth of a stoichiometric film. The method can be applied to many complex materials for which some of the components are volatile.