Effect of Co and Cr Substitution on the Magnetic Properties of Layered Perovskite Manganese Oxide La1.2Sr1.8Mn2O7

The effect of substituting Mn by Co and Cr on the magnetic properties of layered perovskite manganese oxide La1.2Sr1.8Mn2O7 is investigated. Co doping results in the frustration of long-range ferromagnetic (FM) order, weakening of ferromagnetism, and occurring of cluster-glass and spinglass state, indicating that no double-exchange interaction occurs between Co and Mn ions. However, the long-randge FM order still exists as Mn is replaced by Cr, which verifies that there is FM interaction between Mn3+ and Cr3+.