Coupling between the ferroelectric and antiferromagnetic orders inYMnO3
Anomalies in the dielectric constant and loss tangent have been observed in the ferroelectromagnet ${\mathrm{YMnO}}_{3}$ near its N\'eel temperature of \ensuremath{\sim}80 K and below its ferroelectric Curie temperature of \ensuremath{\sim}914 K. These anomalies are indicative of coupling between the ferroelectric and antiferromagnetic orders in this compound. A small but distinct magnetoelectric effect and a magnetoresistive effect up to \ensuremath{\sim}15% were also detected in a magnetic field at 5 T. The results will be contrasted with previous theoretical predictions.