Magnetic nanocheckerboards with tunable sizes in the Mn-doped CoFe2O4 spinel

Formation of magnetically ordered array of two types of rectangular nanorods, similar to 300 nm in length and a few nanometers in size, is achieved in the Mn-doped CoFe2O4 spinel through chemical phase separation mediated by cooperative Jahn-Teller distortions. At room temperature, the magnetic nanorods, with composition close to CoFe2O4, interlace with the paramagnetic counterparts and form a highly organized checkerboard pattern in the cross section. The checkerboard size in the range of similar to 13.8x7.9-similar to 17.3x14.0 nm(2) is tunable with composition and, particularly, with the isothermal annealing time. These three-dimensional nanocheckerboards exhibit a nearly ideal configuration for the patterned perpendicular recording medium. (c) 2007 American Institute of Physics.