Multiferroic Properties of a Bismuth Layer Structured Bi3.25La0.75Ti3O12-(La-0.7 Sr-0.3)MnO3 Solid Solution at Low Temperatures

作者：Kim Nam Hoon; Yoon Eui Jung; Il Cheon Chae; Kim Jeong Seog; Choi Yong Nam

来源：Journal of the Korean Physical Society, 2010, 56(1): 393-398.

DOI：10.3938/jkps.56.393

• Low temperature
• Ferroelectrics
• Ferromagnetic
• Bismuth layer structured
• (Bi2O2)(2+) (A(3)Ti(3)MnO(13))(2-)
• Neutron diffraction
• Ps calculation
• Relaxor type

A bismuth layer structured compound (Bi2O2)(2+) (ATi(3)MnO(13))(2-) (A = Bi-1.25 La1.45Sr0.3) with 4-perovskite blocks was prepared by using a solid-state sintering route with a 3-perovskite block compound B3.25La0.75Ti3O12 and ferromagnetic perovskite (La0.7Sr0.3)MnO3 as raw materials. The spontaneous polarization, dielectric permittivity, and magnetization were characterized at low temperatures. In contrast to the behavior of normal ferroelectrics, the measured saturation polarization, Ps, decreased with decreasing temperature. The dielectric permittivity strongly depended on frequency over a large temperature range. The crystal structure wass analyzed using neutron diffraction data collected at low temperatures (300 K similar to 4 K). The centrosymmetric I4/mmm (a = b approximate to 3.835, c approximate to 40.740 angstrom) and noncentrosymmetric A2(1)am models were tested. The saturation polarization, Ps, was calculated using the atomic displacements from their high symmetry positions (I4/mmm) at high temperatures. The reduction in the measured Ps with decreasing temperature is discussed in relation with the calculated Ps and a relaxor-type ferroelectric nature. The magnetization-temperature curve shows a weak spontaneous magnetic transition at similar to 50 K. The material is both ferroelectric and weakly ferromagnetic at low temperatures.