Investigation of multiferroic behaviour of TbMnO3 nanoplates

Abstract

In the present study, hydrothermally prepared TbMnO3 in plates-like morphology at nanoscale are investigated in multiferroic view point. X-ray diffraction study confirms the orthorhombic phase of as-synthesized TbMnO3. Microstructural features studied by Scanning Electron Microscopy and Transmission Electron Microscopy show the plates-like morphology of as-synthesized TbMnO3 at nanoscale. Local distortions investigated by FT-Raman exhibits redshift in T mode by about 20cm−1 as compared to that of the single crystal. The redshift in T mode is mainly due to defect by tilting of octahedra and respective changes in bond angle of Mn–O(1)–Mn. This is assigned to the size-morphology induced defects. The temperature dependent zero-field-cooled and field-cooled magnetization are measured at H=50Oe and in the temperature range 2–300K. The anomalies in magnetization are obtained at 8 and 42K. Bifurcation of the ZFC and FC curves are observed very close to magnetic transition temperature 42K. The 42K anomaly is related to the sine wave ordering of Mn3+ moment; and 8K anomaly is associated with magnetic ordering of the Tb3+-sublattice propagation vector. The anomalies in the electric properties, ϵ′ (T), tan δ (T), which are noticed within the 28K range, coincide with the temperature of incommensurate–commensurate (or lock-in) magnetic transition of TbMnO3. This study confirms that multiferroic behavior is retained in TbMnO3 nanoplates.