Anomalous magnetic noise in imperfect flat bands in the topological magnet Dy2Ti2O7

Abstract

The spin ice compound Dy_2Ti_2O_7 stands out as the first topological magnet in three dimensions, with its tell-tale emergent fractionalized magnetic monopole excitations. Its real-time dynamical properties have been an enigma from the very beginning. Using ultrasensitive, non-invasive SQUID measurements, we show that Dy_2Ti_2O_7 exhibits a highly anomalous noise spectrum, in three qualitatively different regimes: equilibrium spin ice, a `frozen' regime extending to ultra-low temperatures, as well as a high-temperature `anomalous' paramagnet. We show that in the simplest model of spin ice, the dynamics is not anomalous, and we present several distinct mechanisms which give rise to a coloured noise spectrum. In addition, we identify the structure of the single-ion dynamics as a crucial ingredient for any modelling. Thus, the dynamics of spin ice Dy_2Ti_2O_7 reflects the interplay of local dynamics with emergent topological degrees of freedom and a frustration-generated imperfectly flat energy landscape, and as such should be relevant for a broad class of magnetic materials.

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References in corpus (8)

• Low Temperature Spin Freezing in Dy2Ti2O7 Spin Ice
• Why spin ice obeys the ice rules
• Vacancy defects and monopole dynamics in oxygen-deficient pyrochlores
• Spin Dynamics at Very Low Temperature in Spin Ice Dy${}_2$Ti${}_2$O${}_7$
• Unconventional magnetization processes and thermal runaway in spin-ice Dy${}_2$Ti${}_2$O${}_7$
• Aging, memory, and nonhierarchical energy landscape of spin jam
• Jammed spin liquid in the bond-disordered kagome Heisenberg antiferromagnet
• Nuclear spin assisted quantum tunnelling of magnetic monopoles in spin ice

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• Deconstructing Magnetization Noise: Degeneracies, Phases, and Mobile Fractionalized Excitations in Tetris Artificial Spin Ice
• 2-Form U(1) Spin Liquids: Classical Model and Quantum Aspects
• Thermodynamics and fractal dynamics of nematic spin ice, a doubly frustrated pyrochlore Ising magnet
• Power spectrum of magnetic relaxation in spin ice: anomalous diffusion in a Coulomb fluid
• Scaling study of diffusion in dynamic crowded spaces
• Random Transverse Field Effects on Magnetic Noise in Spin Systems
• Spinon mediation of witness spin dynamics in herbertsmithite
• Hearing the light: stray-field noise from the emergent photon in quantum spin ice