Characteristics of BaxSr1-xTiO3 thin films grown by pulsed laser ablation of rotating split targets of BaTiO3 and SrTiO3
We have grown heterostructures of BaxSr1-xTiO3(BST)/La0.7Sr0.3MnO3(LSMO) on LaAlO3(LAO) substrates by the pulsed laser deposition method. BST films with x=0.2,0.5,0.7 and 0.8 have been prepared using a novel rotating split-target arrangement. The lattice constant of the BST films is found to vary linearly with Ba/Sr ratio. An excellent cube-on-cube epitaxial relationship of (100)BST||(100)LSMO||(100)LAO has also been obtained. Scanning electron microscopy studies have revealed smooth and crack-free BST films with a uniform grain size of about 100 nm. Dielectric measurements, made with patterned Au top electrodes and conducting LSMO bottom layers, have shown a maximum permittivity of approximately 280 at 5 kHz in BST films with x=0.7. P-E loop analyses of the Ba0.7Sr0.3TiO3 and Ba0.8Sr0.2TiO3 films have yielded remnant polarization values of 1.66 and 1.81μC/cm2, respectively.