Second harmonic spectroscopy and control of domain size in antiferromagnetic YMnO3

Abstract
A novel technique for the visualization of antiferromagnetic domains making use of second harmonic generation is used to study the easy-plane antiferromagnet YMnO3. Domain states characterized by small, medium, or large domains are observed. Switching from one state to another can be achieved by a heat treatment above TN and subsequent cooling below TN. Contributions to the mechanism of this unusual behavior of domains are discussed.