Magnetic, dielectric and calorimetric studies on $0.9{\mathrm{BiFeO}}_3–0.1{\mathrm{BaTiO}}_3$ indicate strong magnetoelectric coupling. XRD studies reveal a very remarkable change in the rhombohedral distortion angle and a significant shift in the atomic positions at the magnetic $T_c$ due to an isostructural phase transition. The calculated polarization using Rietveld refined atomic positions scales linearly with magnetization. Our results provide the first unambiguous, atomic level evidence for magnetoelectric coupling of intrinsic multiferroic origin in a ${\mathrm{BiFeO}}_3$-based system.

• Received 5 August 2008

DOI:https://doi.org/10.1103/PhysRevLett.101.247602