Magnetic-field-induced critical dynamics in magnetoelectric TbPO${}_4$

Abstract

We report on the magnetoelectric dynamics in the linear magnetoelectric antiferromagnet TbPO${}_4$ studied by broadband dielectric spectroscopy. For the phase transition into the magnetoelectric antiferromagnetic phase at $T_N\approx 2.3$ K, a finite magnetic field $H$ induces critical behavior in the quasi-static permittivity ${\epsilon }^{\prime }$. Plotting the corresponding anomaly as function of $T/T_N(H)$, we observe the scaling behavior $\Delta {\epsilon }^{\prime }\propto H^2$, a clear fingerprint of linear magnetoelectric antiferromagnets. Above the phase transition, we find a critical slowing down of the ferroic fluctuations in finite magnetic field. This behaviour can be understood via a magnetic-field-induced relaxational response that resembles the soft-mode behaviour in canonical ferroelectrics and multiferroics.

References in corpus (6)

• Dynamical magneto-electric coupling in helical magnets
• Theory of electromagnon in the multiferroic Mn perovskites: Vital role of higher harmonic components of the spiral spin order
• Relaxations as key to the magnetocapacitive effects in the perovskite manganites
• Critical slowing down near the multiferroic phase transition in MnWO${}_4$
• Soft-mode behavior of electromagnons in multiferroic manganite
• Magnetoelectricity in two-dimensional materials