Pulsed laser deposition of stoichiometric potassium-tantalate-niobate films from segmented evaporation targets

The preparation of epitaxial potassium-tantalate-niobate (KTa0.7Nb0.3O3, KTN) films on strontium-titanate substrates by means of pulsed excimer laser evaporation in vacuum is reported. In the most successful deposition experiments, a segmented evaporation target consisting of a semicircular KTN single crystal and a semicircular potassium nitrate pellet was utilized−to our knowledge for the first time; it was thus possible to overcome the otherwise observed partial loss of the volatile potassium and to avoid potassium deficiency in the KTN films. Rutherford backscattering spectrometry and x ray diffraction results indicate that the samples have the desired stoichiometric composition as well as the orientation prescribed by the substrate crystal.