Ultrasonic investigations of spin-ices Dy${}_2$Ti${}_2$O${}_7$ and Ho${}_2$Ti${}_2$O${}_7$ in and out of equilibrium

Abstract

We report ultrasound studies of spin-lattice and single-ion effects in the spin-ice materials Dy${}_2$Ti${}_2$O${}_7$ (DTO) and Ho${}_2$Ti${}_2$O${}_7$ (HTO) across a broad field range up to 60 T, covering phase transformations, interactions with low-energy magnetic excitations, as well as single-ion effects. In particular, a sharp dip observed in the sound attenuation in DTO at the gas-liquid transition of the magnetic monopoles is explained based on an approach involving negative relaxation processes. Furthermore, quasi-periodic peaks in the acoustic properties of DTO due to non-equilibrium processes are found to be strongly affected by {\em macroscopic} thermal-coupling conditions: the thermal runaway observed in previous studies in DTO can be suppressed altogether by immersing the sample in liquid helium. Crystal-electric-field effects having higher energy scale lead to a renormalization of the sound velocity and sound attenuation at very high magnetic fields. We analyze our observations using an approach based on an analysis of exchange-striction couplings and single-ion effects.

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• First order metamagnetic transition in Ho2Ti2O7 observed by vibrating coil magnetometry at milli-Kelvin temperatures
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• An irreversible magnetic-field dependence of low-temperature heat transport of spin-ice compound Dy_2Ti_2O_7 in a [111] field

Cited by in corpus (8)

• Magnetization beyond the Ising limit of Ho${}_2$Ti${}_2$O${}_7$
• Extremely slow non-equilibrium monopole dynamics in classical spin ice
• Investigation of the monopole magneto-chemical potential in spin ices using capacitive torque magnetometry
• Tricritical fluctuations and elastic properties of the Ising antiferromagnet UIrSi${}_3$
• Probing emergent QED in quantum spin ice via Raman scattering of phonons: shallow inelastic scattering and pair production
• Crystal-field magnetostriction of the spin ice under ultrahigh magnetic fields
• Magnetic field tuning of crystal field levels and vibronic states in Spin-ice Ho${}_2$Ti${}_2$O${}_7$ observed in far-infrared reflectometry
• Thermal Conductivity of Square Ice