Impact of Ferroelectric Ordering on Optical and Magnetic Properties of Hexagonal Manganites

Abstract

We show that unusual crystal structure and ferroelectric ordering in hexagonal manganites lead to strong modifications of their electronic structure, and optical and magnetic properties in comparison to perovskite manganites. Second harmonic generation (SHG) is shown to be very sensitive to fine details of magnetic structures and this feature was used to solve the long-standing problem of the magnetic symmetry of the eight hexagonal manganites. SHG of ferroelectric and magnetic types are both allowed and can be applied to the study of ferroelectric and antiferromagnetic domains. A clamping between ferroelectric and antiferromagnetic domain walls is observed and explained as due to piezomagnetic interaction.

Keywords:

• Ferroelectric hexagonal manganites
• electronic structure
• linear optical spectroscopy
• nonlinear optical spectroscopy
• second harmonic generation
• magnetic structures
• magnetic phase diagrams
• ferroelectric domains
• antiferromagnetic domains
• piezomagnetic interaction of ferroelectric and antiferromagnetic domain walls

Acknowledgements

Support by the Deutsche Forschungsgemeinschaft and the Russian Foundation for Basic Research is acknowledged.