Structures and electromagnetic properties of the A-site ordered/disordered manganites; RBaMn2O6/R0.5Ba0.5MnO3 (R = Y and rare earth elements)

The discovery of novel structural and physical properties in the $A$-site ordered manganite $R$BaMn${}_2$O${}_6$ ($R$ = Y and rare earth elements) has demanded new comprehension about perovskite manganese oxides. In the present study, the $A$-site disordered form $R$${}_{0.5}$Ba${}_{0.5}$MnO${}_3$ was successfully synthesized and compared with $R$BaMn${}_2$O${}_6$ in the structures and electromagnetic properties. $R$${}_{0.5}$Ba${}_{0.5}$MnO${}_3$ has a primitive cubic perovskite cell. Unexpectedly the magnetic glassy states are dominant as the ground state for $R$${}_{0.5}$Ba${}_{0.5}$MnO${}_3$. A peculiar behavior, the steplike ultrasharp magnetization and resistivity change, has been observed in Pr${}_{0.5}$Ba${}_{0.5}$MnO${}_3$.