Magnetoelectric properties of Tb_(0.27-x)Dy_(0.73-y)Y_(x+y)Fe_2/PVDF composites

摘要

Synthesis by arc melting, and the structural and electric properties of yttrium-diluted Tb_(0.27-x)Dy_(0.73-y)Y_(x+y)Fe_2 intermetallics were studied by X-ray diffraction (XRD) and four-probe dc electrical measurements. XRD analysis (300 K) shows that all samples crystallize in a cubic, Fd3m, MgCu_2-type structure. The lattice parameter increases along with the yttrium content. Electrical resistivity for the Tb_(0.27-x)Dy_(0.73-y)Y_(x+y)Fe_2 intermetallic series was measured in a temperature range of 15-1100 K. The parameters involved in the dependence of resistivity on temperature were determined. Residual, phonon and magnetic resistivity were separated from the measured electrical resistivity using both the Matthiesen formula and the Bloch-Griineisen formula. Curie temperatures of the compounds were obtained from the magnetic resistivity curves. Magnetoelectric composites containing magnetostrictive Tb_(0.27-x)Dy_(0.73-y)Y_(x+y)Fe_2 grains in a PVDF matrix were prepared. All the composites were characterized by scanning electron microscope observations. The measurements carried out at room temperature as a function of the external DC magnetic field and frequency of the sinusoidal AC modulation magnetic field reveal a distinct magnetoelectric effect of the Tb_(0.27-x)Dy_(0.73-y)Y_(x+y)Fe_2/PVDF composites.