Magnetic enhancement across a ferroelectric–paraelectric phase boundary in Bi1−xSmxFeO3

Structural, vibrational, and magnetic properties of Bi1−xSmxFeO3 (0≤x≤0.20) are investigated by using x-ray powder diffraction, Raman scattering, and magnetometry techniques. We show that the rare-earth ion Sm substitution at Bi site, serving chemical pressure, causes the structural transformation from rhombohedral R3c phase to orthorhombic Pnma phase at x∼0.15, accompanying with the ferroelectric–paraelectric transition. The magnetization is found to be enhanced initially with Sm substitution increasing before approaching ferroelectric–paraelectric boundary but it slightly decreases after passing a maximum. The enhanced magnetization is suggested to stem from the combined effects of the suppressed spin cycloids and increased degree of canting and magnetic interactions between magnetic ions.