Critical behavior study of the spin ordering transition in RVO3 (RÂ =Â Ce, Pr, Nd, Sm, Gd, Er) by means of ac photopyroelectric calorimetry

- Critical behaviour of RVO3 is studied for the first time, on single crystals.
- Thermal diffusivity has been measured and fitted to extract α, A+/A-.
- 3D-XY model agrees with R = Ce, Nd, Sm and Er showing easy-plane magnetism.
- 3D-Ising model agrees with R = Gd due to an easy axis anisotropy.
- 3D-Heisenberg agrees with R = Pr; an effective isotropic description is valid.

The thermal diffusivity of RVO3 single crystals (R = Ce, Pr, Nd, Sm, Gd, and Er) has been measured with an ac photopyroelectric calorimetry in the region in which the G-type orbital ordering and C-type spin ordering take place. Detailed measurements in the close neighbourhood of the spin ordering temperature have allowed to extract the critical parameter α and the critical ratio A+/A− for this transition. While the samples containing Ce, Nd, Sm and Er belong to the 3D-XY universality class (showing that the spins have an easy plane anisotropy), the sample with Gd, which is known to present a clear easy axis, belongs to the 3D-Ising class. Finally, PrVO3 shows an effective isotropic behavior, as the critical parameters found agree with the 3D-Heisenberg class.