Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA.
Phys Rev Lett. 2011 Nov 11;107(20):207206. doi: 10.1103/PhysRevLett.107.207206.
Polarized small-angle neutron scattering studies of single-crystalline multiferroic BiFeO(3) reveal a long-wavelength spin density wave generated by ∼1° spin canting of the spins out of the rotation plane of the antiferromagnetic cycloidal order. This signifies weak ferromagnetism within mesoscopic regions of dimension 0.03 microns along [110], to several microns along [111], confirming a long-standing theoretical prediction. The average local magnetization is 0.06 μ(B)/Fe. Our results provide an indication of the intrinsic macroscopic magnetization to be expected in ferroelectric BiFeO(3) thin films under strain, where the magnetic cycloid is suppressed.
利用偏振小角中子散射研究了单晶多铁性 BiFeO(3)，结果表明在反铁磁旋卷序的旋转面外，自旋发生了约 1°的倾斜，由此产生了长波长自旋密度波。这意味着在 [110]方向上，尺寸为 0.03 微米的介观区域内存在弱铁磁性，在 [111]方向上则延伸到几微米，这与长期以来的理论预测相符。平均局域磁化强度为 0.06 μ(B)/Fe。我们的研究结果表明，在应变条件下抑制磁旋后，铁电 BiFeO(3)薄膜中有望出现固有宏观磁化强度。
