No abstract

According to the molar ratio of 0.71Pb(Mg 1/3 Nb 2/3 )O 3 -0.26PbTiO 3 -0.03Pb(Er 1/2 Nb 1/2 )O 3 , Er 3+ -doped PMNT polycrystalline material was prepared by two-step solid-state synthesis at elevated temperature. Er 3+ -doped PMNT relaxor-based ferroelectric crystal with size of φ25 mm × 100 mm was grown from the stoichiometric melts by vertical Bridgman method. In the ferroelectric crystal with perovskite structure, Er 3+ ions were doped into the crystal lattice via one composition of the ternary solid solution compound. The dielectric, piezoelectric and ferroelectric properties and up-conversion emission performance of Er 3+ -doped PMNT crystal wafers were investigated systematically. It is verified that Er 3+ -doped PMNT crystal presents the similar electrical properties to those of undoped PMNT crystal. Under the excitation of 980 nm, the crystal also exhibits a strong up-conversion fluorescence emission characteristic to Er 3+ ions doped in the medium, and the emission intensity will be enhanced after being poled.

The JA-SW hybrid model is extended in order to include the strain or stress anisotropy. With this improved model, a simulation is carried out to study the effects of stress on magnetic hysteresis loss and coercivity of ferromagnetic film. It is shown that the hysteresis loss and coercivity are related to the external field orientation, the stress intensity and the stress direction. Hysteresis loss, or the coercive force does not entirely monotonially increase with the change of stress intensity. For example, when the external field is parallel to the easy axis, a valley appears in the curve. In addition, stress will cause the peak offset of the coercivity curve as the orientation angle of the external field changes. Extensive comparisons of results with literature data are made and the differences between them are explained.