Non-equilibrium hysteresis and spin relaxation in the mixed-anisotropy dipolar coupled spin-glass LiHo${}_{0.5}$Er${}_{0.5}$F${}_4$

Abstract

We present a study of the model spin-glass LiHo${}_{0.5}$Er${}_{0.5}$F${}_4$ using simultaneous AC susceptibility, magnetization and magnetocaloric effect measurements along with small angle neutron scattering (SANS) at sub-Kelvin temperatures. All measured bulk quantities reveal hysteretic behavior when the field is applied along the crystallographic c axis. Furthermore avalanche-like relaxation is observed in a static field after ramping from the zero-field-cooled state up to $200-300$ Oe. SANS measurements are employed to track the microscopic spin reconfiguration throughout both the hysteresis loop and the related relaxation. Comparing the SANS data to inhomogeneous mean-field calculations performed on a box of one million unit cells provides a real-space picture of the spin configuration. We discover that the avalanche is being driven by released Zeeman energy, which heats the sample and creates positive feedback, continuing the avalanche. The combination of SANS and mean-field simulations reveal that the conventional distribution of cluster sizes is replaced by one with a depletion of intermediate cluster sizes for much of the hysteresis loop.

arXiv comment6 pages, 4 figures

References in corpus (12)

• Memory and Chaos Effects in Spin Glasses
• Aging, rejuvenation and memory effects in Ising and Heisenberg spin glasses
• Slow dynamics and aging in spin-glasses
• Spin Anisotropy and Slow Dynamics in Spin Glasses
• Coherent Spin Oscillations in a Disordered Magnet
• Observation of Spin Glass Dynamics in Dilute LiHo${}_x$Y${}_{1-x}$F${}_4$
• Absence of Conventional Spin-Glass Transition in the Ising Dipolar System LiHo_xY_{1-x}F_4
• A Role of Initial Conditions in Spin-Glass Aging Experiments
• Collective Phenomena in the LiHo_xY_{1-x}F4 Quantum Ising Magnet: Recent Progress and Open Questions
• Using thermal boundary conditions to engineer the quantum state of a bulk magnet
• Finite versus zero-temperature hysteretic behavior of spin glasses: Experiment and theory
• Phase diagram with enhanced spin-glass region of mixed Ising / XY magnets LiHo${}_x$Er${}_{1-x}$F${}_4$

Cited by in corpus (3)

• Neutron spectroscopic study of crystal-field excitations and the effect of the crystal field on dipolar magnetism in Li$R$F${}_4$ ($R$ = Gd, Ho, Er, Tm, and Yb)
• Probing strongly hybrid nuclear-electronic states in a model quantum ferromagnet
• The Effect of Intrinsic Quantum Fluctuations on the Phase Diagram of Anisotropic Dipolar Magnets