Magnetic and magnetoelectric excitations in TbMnO${}_3$

Abstract

Magnetic and magnetoelectric excitations in the multiferroic TbMnO_3 have been investigated at terahertz frequencies. Using different experimental geometries we can clearly separate the electro-active excitations (electromagnons) from the magneto-active modes, i.e. antiferromagnetic resonances (AFMR). Two AFMR resonances were found to coincide with electromagnons. This indicates that both excitations belong to the same mode and the electromagnons can be excited by magnetic ac-field as well. In external magnetic fields and at low temperatures distinct fine structure of the electromagnons appears. In spite of the 90^o rotation of the magnetic structure, the electromagnons are observable for electric ac-fields parallel to the a-axis only. Contrary to simple expectations, the response along the c-axis remains purely magnetic in nature.

5 Pages, 4 figures

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Cited by in corpus (2)

• Terahertz time-domain spectroscopy of electromagnons in multiferroic perovskite manganites
• Model for twin electromagnons and magnetically induced oscillatory polarization in multiferroic RMnO${}_3$