Room temperature ferroelectricity in multiferroic HoMnO<sub>3sub> ceramics
- 作者：P.P. Rout ; S.K. Pradhan ; S.K. Das ; B.K. Roul<sup> ; sup><sup>ims@iopb.res.insup>
- 关键词：Ceramics ; Photoelectron spectroscopy ; Dielectric ; X-ray diffraction ; Ferroelectricity
- 刊名：Physica B
- 出版年：2012
- 期刊代码：53_09214526
- 类别：ph
- 出版时间：15 June, 2012
- 卷：407
- 期：12
- 页码：2072-2077
- 文件大小：544 K
摘要
We have observed good ferroelectric loops at room temperature in hexagonal HoMnO<sub>3sub> (HMO) bulk ceramics sintered at 1250 掳C. Microstructure and ferroelectric hysteresis loops are observed to be dependent on sintering temperature. It is observed that with an increase of sintering temperature, hexagonal a-axis is compressed and c-axis is marginally dilated with overall contraction of the hexagonal unit-cell volume. We explain the origin of ferroelectricity through relative movement of Ho ion and Mn ion within its unit-cell volume, resulting in the distortion of unit-cell volume. We argue that ferroelectric origin of hexagonal HMO at room temperature may be due to the marginal displacement of Ho ion along a-axis, that influences the exchange interaction among the Mn<sup>3+sup> and Ho<sup>3+sup> ions, causing magnetically induced ferroelectricity at room temperature.