Influence of Nd-Co Substitution on Structural, Electrical, and Dielectric Properties of X-Type Hexagonal Nanoferrites

摘要

A series of single phase X-type hexagonal ferrites with concentration Sr_(2-x)Nd_xNi_2Fe_(28-y)Co_yO_(46) (x = 0.02, 0.04, 0.06, 0.08, 0.10 and y = 0.1, 0.2, 0.3, 0.4, 0.5) has been prepared by sol-gel method sintered at 1250℃ for 6 h. The x-ray diffraction analysis reveals the single phase of X-type hexagonal ferrites. The particle size was calculated by using SEM and TEM. The ferrite substituted with Nd~(3+) and Co~(2+) has average particle size in the range of 40-50 nm. The room temperature electrical resistivity experiences the significant enhancement from a value of 1.1 × 10~7 to 2.03 × 10~8 Ωcm with the increase in Nd~(3+) and Co~(2+) concentration. The dielectric constant exhibits high value at low frequencies and decreases with the increase of frequency. The tangent dielectric loss shows the abnormal behavior which can be explained on the basis of hopping between the Fe~(2+) and Fe~(3+) ions on octahedral sites. The maximum value of tangent loss at low frequencies reflects the application of these materials in medium frequency devices (MF).