Effect of cation disorder on structural, magnetic and dielectric properties of La2MnCoO6 double perovskite.

A J Barón-González, C Frontera, J L García-Muñoz, B Rivas-Murias, J Blasco

Index: J. Phys. Condens. Matter 23(49) , 496003, (2011)

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Abstract

The origin of dielectric anomalies and magnetodielectric response of La(2)MnCoO(6) has been investigated by means of ultra-high resolution synchrotron x-ray powder diffraction, neutron powder diffraction, resistivity, magnetization and dielectric measurements. The study has been performed on two different bulk samples presenting different degrees of Mn/Co order: 95 and 74%. Beside the well-known influence on magnetic properties, our results show that the main effect of disorder lies on the electrical resistivity. Bond distances clearly show Mn(4+)/Co(2+) valence states in the well-ordered sample, while for the disordered one this picture still holds. AC resistivity data show dielectric anomalies and a small magnetodielectric effect, but impedance complex plane analyses prove that these phenomena appear at the frequency-temperature region where extrinsic effects dominate the dielectric response.© 2011 IOP Publishing Ltd