Substitution of La and Fe with Dy and Mn in multiferroic La_(1-x)Dy_xFe_(1-y)Mn_yO_3 nanocrystallites

摘要

Nanosized particles of La_(1-x)Dy_xFe_(1-y)Mn_yO_3 were prepared by normal micro-emulsion method involving simultaneous double ions substitution. The particles diameter was found in the range of 11-60 nm as confirmed by X-ray diffraction and scanning electron microscopy analysis. The saturation magnetization (M_s) was improved from 4.62 × 10~3 Am~(-1) to 7.38 × 10~3 Am~(-1), the retentivity (M_r) was increased from 692 Am~(-1) to 3737.75 Am~(-1) while the coercivity was decreased from 4.42 × 10~3 Oe to 3.35 × 10~3Oe as determined by hysteresis loops measurement. The maximum M_s and M_r values were exhibited by Lao.25Dyo.75Feo.25 Mn_(0.75)O_3. The electrical resistivity of La_(1-x)Dy_xFe_(1-y)Mn_yO_3 was increased from 1.65 × 10~8 Ω cm (La_(1.0)Dy_(0.0)Fe_(1.0)Mn_0O_3) to 18.79×10~8 Ω cm (La_(0.5)Dy_(0.5)Fe_(0.5)Mn_(0.5)O_3). The significant improvement in dielectric properties of La_(1-x)Dy_xFe_(1-y)Mn_yO_3 was also observed and maximum dielectric properties (dielectric constant, dielectric loss and dielectric loss factor) were exhibited by La_(0.5)Dy_(0.5)Fe_(0.5)Mn_(0.5)O_3, which is compatible with the electrical properties.