Evidence of cluster-glass-like state at low temperature in anti-site disordered La1.5Ca0.5CoMnO6 double perovskite

Abstract

We have investigated structural and magnetic properties having cluster-glass (CG) like ordering at low temperature in a polycrystalline La1.5Ca0.5CoMnO6 double perovskite sample. In this anti-site disordered double perovskite, ferromagnetic (FM) ordering is observed at ∼157 K. From temperature variation linear ac susceptibility measurements, a CG state is clearly observed below a freezing temperature of ∼50.1 K, the origin of which can be best explained through (1) structural disorder and (2) consequence of the coexistence and competition of antiferromagnetic and FM interactions. The linear complex ac susceptibility data near the freezing temperature are best fitted to a critical slowing down model characterized by the dynamic exponents zυ ∼ 4.95(5) and τ0 ∼ 1.23 × 10−7 s. These values are very similar to what is generally observed in a CG system. The glassy transition temperature versus Hdc23 behaviour follows the Almeida-Thouless line. The time dependent slow relaxation dynamics and aging effect have also been investigated to confirm a CG-like state formation in this compound.