Weak ferromagnetism in BiFeO3 doped with titanium

The Bi(1-x)A(x)Fe(1-x)Ti(x)O(3) (A-Ca, Sr, Pb, Ba) and BiFe1-xTixO3+delta systems have been studied using X-ray, neutron powder diffraction and magnetization measurements in a magnetic field up to 14 T. It was found that all Bi(1-x)A(x)Fe(1-x)Ti(x)O(3) solid solutions are rhombohedral up to x = 0.3. In the case of BiFe1-xTixO3+delta the rhombohedral distortion preserved up to x = 0.11. A homogeneous weakly ferromagnetic state was found for Bi1-xCaxFe1-xTixO3 (0.15 <= x <= 0.25) and BiFe1-xTixO3+delta (0.06 <= x <= 0.11), probably due to magnetoelectric interactions, whereas Bi(1-x)A(x)Fe(1-x)Ti(x)O(3) (A-Sr, Pb, Ba) compounds above doping level x > 0.1 seem to be collinear antiferromagnets. (C) 2009 Elsevier B.V. All rights reserved.