Magnetic chessboard-type nanodomains in Mn-doped CoFe2O4

We examined formation processes of ordered array of two types of rectangular nanorods, characterized as chessboard-type (CB-type) nanodomain structures, by changing the isothermal annealing time at 648 K. Highly organized CB-type nanodomain structures developed through the isothermal annealing treatment from 10 to 730 hours and consequently the CB-type nanodomain structures with ~50 nm2 in size are formed in samples annealed for 730 hours. From the chemical composition analysis, it is revealed that the two types of rectangular nanorods comprise the coexisting state of one nanorod with composition close to CoFe1.4MnO4 with the cubic structure and another nanorod with composition close to CoFe0.4Mn2O4 with the orthorhombic structure.