Senff D, Link P, Hradil K, Hiess A, Regnault L P, Sidis Y, Aliouane N, Argyriou D N, Braden M
II. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, D-50937 Köln, Germany.
Phys Rev Lett. 2007 Mar 30;98(13):137206. doi: 10.1103/PhysRevLett.98.137206. Epub 2007 Mar 29.
The magnetic excitations in multiferroic TbMnO3 have been studied by inelastic neutron scattering in the spiral and sinusoidally ordered phases. At the incommensurate magnetic zone center of the spiral phase, we find three low-lying magnons whose character has been fully determined using neutron-polarization analysis. The excitation at the lowest energy is the sliding mode of the spiral, and two modes at 1.1 and 2.5 meV correspond to rotations of the spiral rotation plane. These latter modes are expected to couple to the electric polarization. The 2.5 meV mode is in perfect agreement with recent infrared-spectroscopy data giving strong support to its interpretation as a hybridized phonon-magnon excitation.
通过在螺旋相和正弦有序相中进行非弹性中子散射，对多铁性TbMnO₃中的磁激发进行了研究。在螺旋相的非公度磁区中心，我们发现了三个低能磁振子，其特性已通过中子极化分析完全确定。最低能量处的激发是螺旋的滑动模式，1.1毫电子伏和2.5毫电子伏处的两个模式对应于螺旋旋转平面的旋转。预计后两种模式会与电极化耦合。2.5毫电子伏的模式与最近的红外光谱数据完全吻合，有力地支持了将其解释为混合声子 - 磁振子激发的观点。
