Experimental observation of magnetoelectricity in spin ice Dy₂Ti₂O₇

Abstract

The intrinsic noncollinear spin patterns in rare-earth pyrochlore are physically interesting, due to their many emergent properties (e.g., spin-ice and monopole-type excitation). Recent works have suggested that the magnetic monopole excitation of spin-ice systems is magnetoelectric active, but this fact has rarely been confirmed via experiment. In this work, we performed a systematic experimental investigation on the magnetoelectricity of Dy 2 Ti 2 O 7 by probing the ferroelectricity, spin dynamics, and dielectric behaviors. Two ferroelectric transitions at T c1 =25 K and T c2 =13 K were observed. Remarkable magnetoelectric coupling was identified below the lower transition temperature, with significant suppression of the electric polarization on applied magnetic field. Our results show that the lower ferroelectric transition temperature coincides with the Ising-spin paramagnetic transition point, below which the quasi-particle-like monopoles are populated, which indicates implicit correlation between electric dipoles and spin moments. The possible magnetoelectric mechanisms are discussed. Our results can be used for more investigations to explore multiferroicity in these spin-ice systems and other frustrated magnets.

Hexagonal phase stabilization and magnetic orders of multiferroicLu1−xScxFeO3Lin1, Zhang2, Liu3 et al. 2016Phys. Rev. B621330View full textAdd to dashboardCite

“…In the high temperature range (300-600 K), the ZFC-FC -T curves were measured in a high vacuum state using a vibrating sample magnetometer (VSM) with the oven option. To probe the ferroelectric polarization (P) at low temperature region, the pyroelectric current method was used, and extrinsic contributions, such as the de-trapped charges, were carefully reduced to a minimal level [34][35]. The temperature-dependent polarization under magnetic field (H) was collected at a warming rate of 4 K/min with a fixed magnetic field during the whole process.…”

Dielectric relaxations in Ho2Ti2O7 and Dy2Ti2O7 pyrochlores

“…Recently, observation of ferroelectricity in these systems has renewed interests in their theoretical and experimental studies [9][10][11]. Experimental finding suggests that HTO and DTO, spin ices have multiple ferroelectric transitions of different origin [12].…”

“…However, in single crystal of HTO, only one transition at 28K has been observed [11]. On the other hand, in polycrystalline DTO two ferroelectric transitions at 25K and 13K have been reported [10]. It has been suggested that ferroelectric transitions at 60K (polycrystalline HTO), 28K (single crystalline HTO) and 25K…”

“…(polycrystalline HTO) and 13K (polycrystalline DTO) are related to the magnetism of these system [9,10].…”

Wasp – Waisted loop and spin frustration in Dy2−xEuxTi2O7 pyrochlore

“…Similar new additional peak (T s ) has also been observed for x = 1.8, 1.9 at higher temperature (T > 23. [44,74,75].…”