Institut de Ciència de Materials de Barcelona, ICMAB-CSIC, Campus Universitari de Bellaterra, E-08193 Bellaterra, Spain.
J Phys Condens Matter. 2011 Dec 14;23(49):496003. doi: 10.1088/0953-8984/23/49/496003. Epub 2011 Nov 22.
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.
通过超高压同步加速器粉末 X 射线衍射、中子粉末衍射、电阻率、磁化率和介电测量研究了 La(2)MnCoO(6)的介电异常和磁电响应的起源。这项研究是在两个具有不同 Mn/Co 有序度的大块样品上进行的：95%和 74%。除了对磁性的明显影响外，我们的结果表明，无序的主要影响在于电阻率。在有序样品中，键距清楚地显示出 Mn(4+)/Co(2+)价态，而对于无序样品，这种情况仍然存在。交流电阻率数据显示出介电异常和较小的磁电效应，但阻抗复平面分析证明这些现象出现在外部分子效应主导介电响应的频率-温度区域。
