A Supercooled Spin Liquid State in the Frustrated Pyrochlore Dy2Ti2O7

TL;DR

This paper reveals that Dy2Ti2O7 exhibits supercooled magnetic liquid behavior with glass-like properties, characterized by specific relaxation dynamics and divergence trajectories, suggesting a transition towards a magnetic glass state.

Contribution

The study introduces high-precision magnetization transport techniques and demonstrates supercooled magnetic liquid behavior in Dy2Ti2O7, a novel finding in frustrated magnetic systems.

Findings

Magnetic susceptibility follows Havriliak-Negami form.

Real-time magnetic relaxation fits Kohlrausch-Williams-Watts form.

Magnetic relaxation rates diverge along Vogel-Tammann-Fulcher trajectory.

Abstract

A "supercooled" liquid develops when a fluid does not crystallize upon cooling below its ordering temperature. Instead, the microscopic relaxation times diverge so rapidly that, upon further cooling, equilibration eventually becomes impossible and glass formation occurs. Classic supercooled liquids exhibit specific identifiers including microscopic relaxation times diverging on a Vogel-Tammann-Fulcher (VTF) trajectory, a Havriliak-Negami (HN) form for the dielectric function, and a general Kohlrausch-Williams-Watts (KWW) form for time-domain relaxation. Recently, the pyrochlore Dy2Ti2O7 has become of interest because its frustrated magnetic interactions may, in theory, lead to highly exotic magnetic fluids. However, its true magnetic state at low temperatures has proven very difficult to identify unambiguously. Here we introduce high-precision, boundary-free magnetization transport techniques based upon toroidal geometries and gain a fundamentally new understanding of the time- and frequency-dependent magnetization dynamics of Dy2Ti2O7. We demonstrate a virtually universal HN form for the magnetic susceptibility, a general KWW form for the real-time magnetic relaxation, and a divergence of the microscopic magnetic relaxation rates with precisely the VTF trajectory. Low temperature Dy2Ti2O7 therefore exhibits the characteristics of a supercooled magnetic liquid; the consequent implication is that this translationally invariant lattice of strongly correlated spins is evolving towards an unprecedented magnetic glass state, perhaps due to many-body localization of spin.