Magnetoelectric studies of antiferromagnetic crystals in strong magnetic fields

Exptl. studies of the magnetoelec. effect in the antiferromagnetic crystals Cr2O3, Gd2CuO4 and Sm2CuO4 were performed in strong magnetic fields up to 20 T. The magnetoelec. effect is fully detd. by the symmetry of the magnetically ordered material and yields hence valuable information about magnetic ground states. When the magnetic symmetry is changed at a magnetic field induced phase transition the magnetoelec. effect exhibits anomalies at the phase transition owing to the fact that the magnetoelec. signal is related to the antiferromagnetic order parameter L. Even at temps. close to the Neel temp. TN the obtained exptl. data resolve the magnetic properties very well, giving the possibility to study magnetic phase transitions in the crit. temp. range