Magnetic excitations near the quantum phase transition in the Ising ferromagnet LiHoF4

Effective-medium theory and inelastic neutron scattering are used to study the magnetic excitations in the Ising ferromagnet LiHoF4 near its magnetic-field-induced quantum phase transition (QPT). As expected, the dominant mode softens at the QPT, but reaches a finite, rather than vanishing, limit due to the hyperfine interaction. The experimental phase diagram and excitation spectra are well described by an effective-medium theory to first order in the 1/z expansion. There are some differences between theory and experiments, which may be due to domain walls, their dynamics and shape effects, and to magnetoelastic couplings.


Published in:
PHYSICAL REVIEW B, 75, 5, -
Year:
2007
Publisher:
COLLEGE PK, AMERICAN PHYSICAL SOC
ISSN:
1098-0121
Laboratories:




 Record created 2009-04-02, last modified 2018-03-17


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