Magnetoelectric effect of TmMn₂O₅

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.

Key Words:

• Ferroelectricity
• helical magnetic ordering
• magnetoelectric effect
• rare earth manganese oxide
• TmMn₂O₅