マルチフェロイック複合材料の電気磁気特性に及ぼす非軸分極処理の影響

抄録

  A multiscale simulation is presented for polycrystalline multiferroic composite materials consisting of ferroelectric and ferromagnetic phases. The purpose of this study is to estimate the effect of off-axis electric and magnetic polarization on macroscopic magnetoelectric (ME) coupling constants. The asymptotic homogenization theory was employed for scale-bridging between macrostructure and microstructure. The crystal orientations and material types were randomly allocated into the microstructure. Especially the microstructural crystal orientations were controlled by the combination of off-axis electric and magnetic polarization treatments. Tetragonal perovskite BaTiO₃ and hexagonal spinel CoFe₂O₄ were employed for ferroelectric and ferromagnetic phases, respectively. As the angle between electric and magnetic fields of polarization treatment was changed from 0 to 90 degree, the homogenized physical properties were calculated for the polycrystalline multiferroic composite material. The computation indicated the macroscopic ME constants and piezomagnetic constants vary more widely through off-axis polarization treatment than the other properties. It was confirmed that ME constants can be tailored by the combination between electric and magnetic polarization treatments.