Critical behavior of the ferromagnetic perovskites RTiO₃ (R = Dy, Ho, Er, Tm, Yb) by magnetocaloric measurements

Ferromagnetism in perovskites RTiO₃ can be induced by a steric effect. The way in which the subtle local structural change can induce three-dimensional (3D) ferromagnetic coupling through Ti-O-Ti superexchange interactions remains controversial. A critical behavior study for the ferromagnetic phase has been made so far only on YTiO₃ because the magnetization measurements are plagued by the contribution from the magnetic rare earth. Here we report critical exponents for most ferromagnetic members in the RTiO₃ family by measuring the magnetocaloric effect and applying the corresponding scaling laws. Our results indicate that the ferromagnetic coupling in the RTiO₃ can be well described by the 3D Heisenberg model.