Magnetic Nanocheckerboards with Tunable Sizes in the Mn-Doped CoFe$_{2}$O$_{4}$ Spinel

In the Mn-doped CoFe$_{2}$O$_{4}$ spinel, a highly ordered array of two types of rectangular nanorods, $\sim $300 nm in length and a few nanometer in size, is achieved through chemical phase separation mediated by cooperative Jahn-Teller distortions. At room temperature, the magnetic nanorods with composition close to CoFe$_{2}$O$_{4}$ interlace with the paramagnetic counterparts and form a highly organized checkerboard pattern in the cross section. The checkerboard size, varying in the range of $\sim $3 nm and $\sim $80 nm, is tunable with composition as well as with the isothermal annealing time This may be of potential significance to the next generation magnetic storage. The magnetic nanocheckerboards exhibit a nearly ideal configuration for perpendicular recording media.