Critical behavior and effect of Sr substitution in double perovskite Ca2CrSbO6 *

Abstract

The double perovskite Ca2CrSbO6 exhibits a ferromagnetic long-range order below T c = 13 K and a saturation magnetization of 2.35 μ B at 2 K. In this study, the polycrystalline Ca2CrSbO6 is synthesized under high pressure and high temperature, and the critical behavior of the ferromagnetic material as well as the effects of the magnetic behavior due to the isovalent substitution of Sr2+ for Ca2+ is investigated. Also studied are the ferromagnetic criticality of the double perovskite Ca2CrSbO6 at the ferromagnetic transition temperature T c ≈ 12.6 K from the isotherms of magnetization M(H) via an iteration process and the Kouvel–Fisher method. The critical exponents associated with the transition are determined as follows: β = 0.322, γ = 1.241, and δ = 4.84. The magnetization data in the vicinity of T c can be scaled into two universal curves in the plot of M/| ε | β versus H/| ε | β + γ , where ε = T/T c – 1. The obtained β and γ values are consistent with the predicted values from a three-dimensional Ising model. The effects of Sr substitution on the double perovskite Ca2CrSbO6 are taken into consideration. As the Sr content increases, the (Ca2 – x Sr x )CrSbO6 polycrystal shows a continuous switch from ferromagnetic to antiferromagnetic behavior.