When Fe ions in the ferrimagnetic cubic MgFe2O4 are replaced by Jahn-Teller (JT)-active Mn ions, the structure evolves with two-step processes. For example, the quenched cubic MgMn1.5Fe0.5O4 becomes tetragonal and JT distorted with slow cooling. However, with further slow cooling, the clustering tendency of JT-distorted Mn ions induces the formation of a checkerboard nano-self-assembly consisting of Mn-rich (tetragonal, paramagnetic) and -poor (cubic, ferrimagnetic) rods. This morphological evolution accompanies a drastic modification of ferrimagnetic properties, e.g., the magnetic coercivity changes by ∼25⁠. The nanocheckerboard assembly with ferrimagnetic nanorods with large shape anisotropy can be a platform for ultra high-density memory devices.

Topics
Jahn-Teller distortion, Magnetic anisotropy, Magnetic materials, Magnetic ordering, Phase transitions, X-ray diffraction, Magnetic nanostructures, Nanorods, Memory device, Perpendicular magnetic recording
© 2007 American Institute of Physics.
2007
American Institute of Physics
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