Effect of the Cr doping on the stable charge ordering (CO) in the spinal compound AlV 2O 4 was investigated by transmission electron microscopy. It is found that the stable CO is destabilized drastically by substituting Cr ions for V ones and the long-ranged CO in AlV 2O 4 becomes short ranged. The size of the CO microdomains in AlV 2-xCr xO 4 with x=0.125 was estimated to be about 10-20 nm. Furthermore, high-resolution lattice images revealed fine mixture of the CO and charge disordered microdomains in AlV 2-xCr xO 4 at room temperature. In addition, we found the presence of the characteristic diffuse scattering due to local lattice distortion induced by the Cr substitution in AlV 2-xCr xO 4. Our results suggested that doped Cr 3+ ions should serve as a quenched "charge" impurity in the CO structure of AlV 2O 4, which is characterized as the charge frustration system.
|Physical Review B - Condensed Matter and Materials Physics
|Published - 2005 2月 1
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