Fabrication And Characterizations Of Bi_3.15Nd_0.85Ti₃O₁₂-CoFe₂O₄ And DyMnO₃ Multiferroic Thin Films

In the past decades, there has been a continually increasing interest in multiferroic materials due to their attractive physical properties and their potential applications as multifunctional devices. In this work, we have synthesized xBi3.15Ndo.85Ti3012-(1-x)CoFe204 (BNdT-CFO) composite thin films, characterized the ferroelectric and ferromagnetic properties, as well as the magnetoelectric (ME) effect at room temperature. We have also tried to deposit epitaxial multiferroic DyMnO3 thin films on various substrates and have studied the structure and morphology as a function of pulsed laser deposition parameters.Multiferroic xBi3.15Nd0.85Ti3012-(1-x)CoFe204 composite thin films with x=0.5,0.6, 0.75 have been prepared by a chemical solution deposition process employing spin-coating technique. X-ray diffraction and scanning electron microscopy reveal that there exists local aggregation or phase separation of BNdT and CFO phases in the films. The composite films exhibit both good ferroelectric and magnetic properties at room temperature, and an obvious room temperature magnetoelectric coupling has also been detected.Multiferroic DyMnO3 thin films have been prepared by pulsed laser deposition on several different substrates. It is found that the orientation of DyMnO3 films are sensitively dependent on the substrates and deposition conditions. An excellent epitaxial hexagonal DyMnO3 film was achieved on the (111) YSZ substrate; DyMnO3 film on the (0001)Al2O3 substrate was a highly textured c-axis oriented film rather than a fully epitaxial one because of the large lattice mismatching between the DyMnO3 and the A12O3 substrate; DyMnO3 film grown on the (111) Pt/Ti/SiO2/Si substrate is polycrystalline; In the case of the (111) SrTiO3 substrate, the DyMnO3 thin film is orthorhombic phase. The DyMnO3 film deposited on (111)YSZ substrate shows a clear hysteresis at 4.2 K, indicating the possible ferromagneticity at 4.2K.