Studies of Ferroelectric and Magnetic Phase Transitions in Pb_(1-x)A_xFe_(1/2)Nb_(1/2)O_3 (A-Ca, Ba) Solid Solutions

摘要

Dielectric and Mossbauer studies of Pb_(1-x)A_xFe_(1/2)Nb_(1/2)O_3 (A- Ba, Ca) ceramic compositions show that the Neel temperature in these solid solutions drops down at x ≈0.15-0.20. At the same threshold the polarization also loses its long-range order and compositions with x > 0.1 exhibit relaxor behavior. The data obtained suggests that there exists a Pb-mediated superexchange controlling the long-range anti ferromagnetic order. Thus, studied multifunctional solid solutions demonstrate the possibility of controlling the magnetic and ferroelectric properties simultaneously by changing the concentration of nonmagnetic lead cations only.