Magnetoelectric Properties Of BiFeO₃-based Mutliferroic Materials

Among all multiferroics, BFO, has certainly been the most studied as it orders both antiferromagnetically and ferroelectrically well above300K. Importantly, the magnetoelectric coupling between these orders potentially enables the manipulation of the ferroelectric polarization by a magnetic field, and the control of magnetic properties by an electric field, this coupling makes it a good candidate material for advanced photonic devices such as electrooptical modulators operating over a broad range of temperature and frequency. The main research work and contents are listed as follows:We prepared BFO nanoparticles by sol-gel method. X-ray diffraction analysis indicat-ed that the sample form single phase sincered at550℃for1.5h. BFO samples behave multiferroic properties with remnant polarization and magnetization0.17μC/cm2and0.25emu/g, saturated magnetization1.17emu/g, Ec=34kv/cm and Hc=174Oe. At frequency of13.52GHz the real part of permittivity increases with the proportion of13.8%with the influence of extra-magnetic field. Meanwhile the real part of perme-ability decrease from1.375to1.175. In addition, microwave absorbing properties of sample is fine with the thickness of3mm, and the return loss of-11dB was obtained at13GHz.We prepared Bi1-xNdxFeO3(x=0.05,0.1,0.15) nanoparticles by sol-gel method. X-ray diffraction analysis indicated that the lattice structure shift from rhombus perovskite structure to cubic perovskite structure. BNFO samples behave multiferroic properties and are superior compared with BFO sample. The real part of permittivity and per-meability behave resonance property. Microwave absorbing properties of BNFO-2is superior and RL is-16dB obtained at11.7GHz. At frequency of11.52GHz the real part of permittivity increases from3.1to3.6with the influence of extra-magnetic field. Meanwhile the real part of permeability decrease from1.58to1.48.We prepared Bi1-xSmxFeO3(x=0.04,0.08,0.12) nanoparticles by sol-gel method. The real part of permittivity and permeability behave resonance property. Microwave ab-sorbing properties of BSFO-3is superior and RL is-14dB obtained at11.22GHz nearby. At frequency of11.22GHz the real part of permittivity increases from4.32to4.6with the influence of extra-magnetic field. Meanwhile the real part of permeability decrease from1.595to1.55.We prepared Bi0.96Smo.o4Fe1-xMnx03(x=0.05,0.1,0.15) nanoparticles by sol-gel method. BSFMO samples behave multiferroic properties with remnant magnetization and po-larization are2.7times BFO. Microwave absorbing properties of BSFMO-2is superior and RL is-20.25dB obtained at12.8GHz nearby. At frequency of11.29GHz the real part of permittivity increases with the influence of extra-magnetic field. Meanwhile the real part of permeability decreases.