Preparation and physical properties of lanthanum-modified Srl-xBaxNb2O6, ferroelectric crystals

The growth parameters and some physical properties of lanthanum-modified strontium barium niobate crystals, grown by the Czochralski method, have been investigated. Crystals were grown from melts having lanthana, La₂O₃ concentrations ranging from 0.01 to 1.50% (by weight;, the Sr to Ba ratio was one. Knoop microhardness was measured as a function of La content and the hardness was found to decrease with increasing La content. Room temperature compressive strength measurements were also made. None of the samples tested exhibited yielding. Fracture stresses did not change in a sensible manner as a function of La content. Lattice parameter measurements were made using x-ray diffraction and showed that the ‘c’ parameter decreased while the ‘a’ parameter increased slightly with increasing La content.