Dielectric and magnetic properties of bulk and layered tape cast CoFe2O4–Pb(Fe1/2Ta1/2)O3 composites

✍ Scribed by J. Kulawik; P. Guzdek; D. Szwagierczak; A. Stoch

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 838 KB
• Volume: 92
• Category: Article
• ISSN: 0263-8223
• DOI: 10.1016/j.compstruct.2009.08.053

✦ Synopsis

The microstructure, dielectric and magnetic properties of bulk and layered CoFe 2 O 4 -Pb(Fe 1/2 Ta 1/2 )O 3 composites were studied. Ceramic samples based on previously mixed ferrite and relaxor powders were sintered at 950 °C. Ferrite and relaxor green tapes 150 lm thick were prepared by tape casting, then cut, stacked alternately, laminated and co-sintered at 950 °C. High and broad maxima of dielectric permittivity reaching 2000 at 1 kHz were found for bulk CoFe 2 O 4 -Pb(Fe 1/2 Ta 1/2 )O 3 ceramic. Measurements of the magnetization of the investigated composites as a function of magnetic field and temperature exhibited behavior typical of hard magnetic materials. The layered composites showed lower coercivity, higher saturation magnetization and a higher magnetoelectric coefficient than the bulk ceramics. Distinct changes in field-and zero field-cooled magnetization curves at À200 °C could be ascribed to the antiferromagnetic transition of the PFT relaxor phase. Multilayer CoFe 2 O 4 -Pb(Fe 1/2 Ta 1/2 )O 3 composites exhibited a magnetoelectric coefficient of 200 mV/(cm Oe) at a frequency of the modulation magnetic field equal to 5 kHz.