Photosensitivity of La2CuO4 in the vicinity of the phase boundary antiferromagnet-spin glass

Abstract

The spectral, temperature and magnetic field dependencies of the linear dichroism in the reflection of light from the surface of an undoped single crystal of La2CuO4 are studied. The changes of the dichroism absolute value and its response to the external magnetic field induced by a weak optical illumination were detected. The set of experimental results is analyzed from the point of view of the high sensitivity of optical and magnetic properties of cuprates to the density of charge carriers localized in CuO2 planes. It is assumed that the poor reproducibility of some of the observed effects is related to the proximity (on the x-T diagram of magnetic states) to the antiferromagnet - spin glass phase boundary.