Enhanced Exchange Bias Effect By Modulating Relative Ratio Of Magnetic Ions In Y2co2-Xmnxo6 (X=1.0-1.9)

It has recently been reported that the exchange bias (EB) phenomenon in double-perovskite Y2CoMnO6 ceramic arises from additional antiferromagnetic (AFM) clusters formed by the anti-sites of ionic disorders in the dominant ferromagnetic (FM) phase. To extensively examine the role of ionic orders and versatile magnetic interactions, we measure the magnetic properties of Y2Co2 - xMnxO6 (x = 1.0-1.9) compounds with different relative ratios of the magnetic ions. Upon increasing the ratio of Mn ions, the FM transition temperature is gradually lowered with a greatly enhanced EB effect for x >= 1.4. The measurement of heat capacity and AC magnetic susceptibility in the compound with x = 1.5 suggests the formation of magnetic cluster-glass state from short-range FM order with comparable AFM clusters generated by the formation of Mn3+-O2--Mn3+ bonds. The dependence of the EB effect on the cooling field reveals the maximum EB field at 2 K to be H-EB = 3.19 kOe. The large EB effect originates from the adjusted proportions of FM and AFM phases and the improved interfacial pinning of exchange coupling in the cluster-glass state. Our results, based on intricate magnetic correlations and phases, provide essential clues for exploring suitable ceramic compounds for magnetic functional applications.