We have studied the temperature $\left(T\right)$ dependence of the dielectric constant of multiferroic $\mathrm{Dy}{\mathrm{Mn}}_2{\mathrm{O}}_5$ under magnetic field $\left(H\right)$ and pressure $\left(P\right)$ to map out a complete $T\text{−}H\text{−}P$ phase diagram. Our $\epsilon (T,H,P)$ data show that most of the phase transitions are rather insensitive to applied field and pressures, except for the two phase transitions seen near 27 and $18\mathrm{K}$, respectively. These two transitions appear to merge into one transition above $12\mathrm{T}$, and this critical field moves toward lower magnetic fields upon application of external pressure. We also found that there is significant magnetoelectric effect right up to $17\mathrm{T}$. We will discuss our findings in light of the intricate interplay of many degrees of freedom in this interesting system.

• Received 25 March 2007

DOI:https://doi.org/10.1103/PhysRevB.76.012406