Please use this identifier to cite or link to this item: http://hdl.handle.net/2445/10662
Title: Resonant spin tunneling in small antiferromagnetic particles
Author: Luis, F.
Barco, Enrique del, 1968-
Hernández Ferràs, Joan Manel
Remiro, E.
Bartolomé, J.
Tejada Palacios, Javier
Keywords: Materials magnètics
Propietats magnètiques
Magnetic materials
Magnetic properties
Issue Date: 1999
Publisher: The American Physical Society
Abstract: The paper reports a detailed experimental study on magnetic relaxation of natural horse-spleen ferritin. ac susceptibility measurements performed on three samples of different concentration show that dipole-dipole interactions between uncompensated moments play no significant role. Furthermore, the distribution of relaxation times in these samples has been obtained from a scaling of experimental X" data, obtained at different frequencies. The average uncompensated magnetic moment per protein is compatible with a disordered arrangement of atomic spins throughout the core, rather than with surface disorder. The observed field dependence of the blocking temperature suggests that magnetic relaxation is faster at zero field than at intermediate field values. This is confirmed by the fact that the magnetic viscosity peaks at zero field, too. Using the distribution of relaxation times obtained independently, we show that these results cannot be explained in terms of classical relaxation theory. The most plausible explanation of these results is the existence, near zero field, of resonant magnetic tunneling between magnetic states of opposite orientation, which are thermally populated.
Note: Reproducció digital del document publicat en format paper, proporcionada per PROLA i http://dx.doi.org/10.1103/PhysRevB.59.11837
It is part of: Physical Review B, 1999, vol. 59, núm. 18,p. 11837 - 11846
URI: http://hdl.handle.net/2445/10662
ISSN: 0163-1829
Appears in Collections:Articles publicats en revistes (Física de la Matèria Condensada)

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