Elastic relaxations associated with the – transition in LaAlO3: I. Single crystal elastic moduli at room temperature

Abstract

Values for all six independent components of the elastic modulus tensor of LaAlO3 perovskite are reported. These were determined by means of Brillouin scatteringmeasurements of acoustic velocities in single crystal plates cut parallel to (110) and(100), as defined with respect to the cubic parent structure, and by pure-modelongitudinal and transverse sound velocity measurements along [100], [110] and[111] directions using GHz pulse-echo ultrasonics. The crystals contained intimateintergrowths of twins arising from the transition at higher temperature but, in combination with a careful analysis of twin orientationrelationships, the two sets of data have allowed a unique solution to be obtained for individual twincomponents. The new data set represents an important contribution to the characterization ofLaAlO3 single crystals which are widely used as the substrate for a plethora of different thin filmswith technological applications.