Change in magnetic properties of La2MnCoO6 in composite with CaCu3Ti4O12

Abstract The magnetic properties of double perovskite La2MnCoO6 (LCMO) by making a composite with ordered double perovskite CaCu3Ti4O12 (CCTO) have been investigated. The composites were prepared by mixing the prior synthesized pure phases of LCMO and CCTO at different mole ratio. We observed that a new low temperature ferromagnetic phase (TC ∼ 110 K) with lower magnetization value evolved at the expense of a high temperature ferromagnetic phase (TC ∼ 228 K). The latter ferromagnetism is associated with ordering of Mn4+ and Co2+ ions. The new magnetic phase could be correlated to vibronic superexchange interaction between Mn3+—O—Co3+ cations, which would establish a ferromagnetic state. The genesis of this magnetic phase can be attributed to the local structural modulation of LCMO across the grain boundary in contact with CCTO. The lower magnetic moments and low temperature transitions have been attributed to the atomic disorder antiferromagnetic interactions (Mn4+—O—Mn4+and Co2+—O—Co2+) akin to parent LCMO.