Investigation of dielectric and magnetic nature of Bi7Fe3Ti3O21

Ceramic samples of Bi7Fe3Ti3O21 were prepared by a solid-state sintering ro ute. X-ray diffraction showed that the material is single phase and isostru ctural with other bismuth layer structured ferroelectrics (BLSFs). Dc condu ctivity measured from room temperature to 640 degrees C showed two slope ch anges. Dielectric measurements carried out in the temperature range 30-850 degrees C indicated dielectric anomalies at 645 and 820 degrees C. A pyroel ectric signal was also measured and the coefficient evaluated. Magnetizatio n measurements indicated that the material is antiferromagnetic in the temp erature range 80-300 K, with a small hysteresis at room temperature. The pr operties are compared with other isostructural compounds. (C) 1999 Elsevier Science Ltd.