Abstract
Based on the measurements of pyroelectricity, dielectric constant, magnetization and magnetoelectric effect, we conclude that TmMn2O5 is ferroelectric below the Curie temperature of 36 K. There are two other transitions at 26 K and 6 K. The phase below 6 K undergoes a transition into another phase at about 5 kOe, possibly the reorientation of the Tm3+ moments. The dielectric properties change remarkably at this transition, indicating a strong interaction between electric and magnetic orders. Magnetic phase diagram at low temperatures is determined from the results of magnetic and dielectric measurement.