Magnetodielectric Response of the Spin-Ice Dy2Ti2O7

TL;DR

This study investigates the magneto-dielectric response of Dy2Ti2O7, revealing how dielectric properties reflect local spin correlations and phase transitions in a geometrically frustrated spin-ice system at very low temperatures.

Contribution

It demonstrates that the magneto-dielectric response can serve as a sensitive local probe of spin states in spin-ice materials, providing detailed phase diagrams.

Findings

Dielectric constant decreases below 1.2 K indicating spin-ice formation

Real part of dielectric constant relates to local spin correlations

Constructed a precise field-temperature phase diagram

Abstract

We report the magneto-dielectric response of single crystals of the spin-ice compound Dy2Ti2O7 down to 0.26 K. The dielectric constant under zero magnetic field exhibits a clear decrease reflecting the development of the local two-spins-in, two-spins-out structure below about 1.2 K. Both the real and imaginary parts of the dielectric constant under magnetic fields sensitively respond to various changes in the spin structures. We found that the real part can be described in terms of local spin correlations among the moments of tetrahedra, rather than among individual Dy3+ moments. Using the peaks in the imaginary part, we have constructed a precise field-temperature phase diagram in the [111] field direction. We thus demonstrate that the magneto-dielectric response can be a high-sensitivity local probe of the spin state of geometrically frustrated systems.