Chemical solution processing and characterization of highly oriented (Ba,-Ln)Nb2O6 [Ln: La, Gd, Dy] thin films

Crack-free and highly oriented (Ba,Ln)Nb2O6 [Ln: La,Gd, Dy] thin films have been synthesized by a chemical solution deposition (CSD) method. Homogeneous and stable (Ba(0.75)Ln(0.167))Nb2O6 precursor solutions were prepared by optimizing the reaction of metal alkoxides in solution. La, Gd, Dy-substituted BaNb2O6 powders and thin films, such as Ba0.75La0.167Nb2O6 (BLN75), Ba0.75Gd0.167Nb2O6 (BGN75) and Ba0.75Dy0.167Nb2O6 (BDN75), crystallized into the tetragonal tungsten bronze phase above 700degreesC. The synthesized BLN75, BGN75 and BDN75 thin films on Pt(100)/MgO(100) had a remarkable c-axis preferred orientation and exhibited the diffuse phase transition of epsilon-T curves. The Curie temperatures of the (Ba(0.75)Ln(0.167))Nb2O6 films were found to depend upon the ionic radii of substituted rare earth ions. The BLN75 and BGN75 thin films on Pt(100)/MgO(100) showed typical ferroelectric hysteresis loops below the Curie temperature.