High elastic modulus in -axis-oriented single crystal VO

The elastic moduli of V2O5 are of great importance for the assessment of the buildup of strain during thin-film growth as well as for the analysis of defect generation and propagation. The usually rather small crystal dimensions make a precise experimental determination of the elastic constants highly challenging and only very little is known about the temperature dependent strain evolution. Here large V2O5 single crystals grown with different parameter sets are investigated by ultrasonic pulse experiments and by sampled continuous wave ultrasound spectroscopy. The elastic modulus C22 is determined to be 220GPa at room temperature. Temperature dependent investigations of the elastic behavior show that ultrasonic experiments are suitable for highly sensitive detection of oxygen-deficient phases in rapidly grown samples. In addition they indicate the presence of temperature dependent elastic instabilities in inhomogeneous samples.