Critical behavior of single-crystal double perovskite Sr2FeMoO6

The critical behavior of the double perovskite Sr2FeMoO6 (SFMO) is investigated by measurements of the magnetization (M), susceptibility (chi), and temperature derivative of the resistivity (drho/dT), the last of which has the same critical exponent as the magnetic heat-capacity anomaly. The critical temperatures determined by both magnetization and drho/dT, are consistent and the critical exponents indicate that this material belongs to a three-dimensional Heisenberg ferromagnet universality class like such conventional metallic ferromagnets as Ni or Fe. We also show the existence of an extraordinary large magnetic resistivity temperate coefficient such as that of SrRuO3.