The existence of a wide distribution of low energy excess magnetic states due to topological disorder in a magnetic glass is confirmed experimentally for the case of terbium metaphosphate glasses with compositions in the vicinity of (Tb2O3)0.25(P2O5) 0.75. A broad peak with a maximum at 7.5 K is found in the magnetic contribution to the specific heat; this has its origin in the excess magnetic states. There is also a residual magnetic contribution from these states to the inelastic neutron scattering, which has been isolated by subtraction of the phonon contribution. Exploiting the paramagnetic behaviour, a novel method of neutron scattering has been investigated, which can be used to isolate the Tb-Tb correlation distances in terbium metaphosphate glass. This method uses the fact that neutrons are sensitive to changes in scattering lengths, and the scattering length of a paramagnetic rare earth ion, in a metaphosphate glass host, can be changed by applying a magnetic field.

A study of low energy magnetic excitations in terbium metaphosphate glass

CARINI, Giuseppe;D'ANGELO, Giovanna;TRIPODO, Gaspare
2003

Abstract

The existence of a wide distribution of low energy excess magnetic states due to topological disorder in a magnetic glass is confirmed experimentally for the case of terbium metaphosphate glasses with compositions in the vicinity of (Tb2O3)0.25(P2O5) 0.75. A broad peak with a maximum at 7.5 K is found in the magnetic contribution to the specific heat; this has its origin in the excess magnetic states. There is also a residual magnetic contribution from these states to the inelastic neutron scattering, which has been isolated by subtraction of the phonon contribution. Exploiting the paramagnetic behaviour, a novel method of neutron scattering has been investigated, which can be used to isolate the Tb-Tb correlation distances in terbium metaphosphate glass. This method uses the fact that neutrons are sensitive to changes in scattering lengths, and the scattering length of a paramagnetic rare earth ion, in a metaphosphate glass host, can be changed by applying a magnetic field.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11570/1584805
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