Resonant Ultrasound studies of spin- and orbital ordering transitions in RVO$_{3}$*

RVO$_{3}$ perovskites (R = rare earth) have been shown to undergo multiple spin and orbital transitions due to the Jahn-Teller active V$^{3+}$ electrons. We have initiated a study of the elastic response of RVO$_{3}$, ( R = Dy, Gd, Ce) as well as Y$_{1-x}$La$_{x}$VO$_{3}$ (x = 0.05, 0.3, 1) using resonant ultrasound spectroscopy. The temperature-dependence of the elastic response is dominated by the ordering transitions, with transition temperatures that change with the size of the rare earth. For CeVO$_{3}$ and LaVO$_{3}$, two transitions are observed, separated by 17K and 2K, respectively. DyVO$_{3}$ and Y$_{0.95}$La$_{0.05}$VO$_{3}$ show three transitions below 220K while GdVO$_{3}$ only shows one. The full elastic tensor of Y${_0.7}$La$_{0.3}$VO$_{3}$ has also been determined from 300K to 50K, yielding the temperature dependence of the 9 orthorhombic elastic moduli.