Electron- and Hole-Doping Effects on $A$-Site Ordered NdBaMn2O6

We have investigated electron- and hole-doping effects on $A$-site ordered perovskite manganite NdBaMn 2 O 6 , which has the $A$-type (layered) antiferromagnetic (AFM) ground state. Electrons (holes) are introduced by partial substitution of Ba 2+ (Nd 3+ ) with Nd 3+ (Ba 2+ ). Electron-doping generates ferromagnetic (FM) clusters in the $A$-type AFM matrix. With increasing the electron-doping level, the volume fraction of the FM phase or the number of the FM clusters is abruptly increasing. In contrast, the $A$-type AFM phase is robust against the hole-doping, and no FM correlation is observed in the hole-doped NdBaMn 2 O 6 .