Nonequilibrium hysteresis and spin relaxation in the mixed-anisotropy dipolar-coupled spin-glass LiHo0.5Er0.5F4

Piatek, J. O.; Kovacevic, I.; Babkevich, P.; Dalla Piazza, B.; Neithardt, S.; Gavilano, J.; Krämer, Karl; Rønnow, H. M. (2014). Nonequilibrium hysteresis and spin relaxation in the mixed-anisotropy dipolar-coupled spin-glass LiHo0.5Er0.5F4. Physical review. B - condensed matter and materials physics, 90(17), p. 174427. American Physical Society 10.1103/PhysRevB.90.174427

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We present a study of the model spin-glass LiHo0.5Er0.5F4 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, avalanchelike 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.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Chemistry, Biochemistry and Pharmaceutical Sciences (DCBP)

UniBE Contributor:

Krämer, Karl

Subjects:

500 Science > 530 Physics
500 Science > 540 Chemistry

ISSN:

1098-0121

Publisher:

American Physical Society

Language:

English

Submitter:

Karl Krämer

Date Deposited:

13 Mar 2015 17:04

Last Modified:

26 Jun 2016 01:59

Publisher DOI:

10.1103/PhysRevB.90.174427

ArXiv ID:

1411.5813v1

BORIS DOI:

10.7892/boris.65116

URI:

https://boris.unibe.ch/id/eprint/65116

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