Volume 72, Number 1, October 2005
|Page(s)||110 - 116|
|Section||Condensed matter: electronic structure, electrical, magnetic, and optical properties|
|Published online||31 August 2005|
Anisotropy in ferromagnetic nanoparticles: Level-to-level fluctuations of a collective effect
Instituto Balseiro and Centro Atómico Bariloche - (8400) Bariloche, Argentina
2 Department of Physics, Duke University - Durham, NC 27708-0305, USA
Accepted: 4 August 2005
We calculate the mesoscopic fluctuations of the magnetic anisotropy of ferromagnetic nanoparticles; that is, the effect of single-particle interference on the direction of the collective magnetic moment. A microscopic spin-orbit Hamiltonian considered as a perturbation of the much stronger exchange interaction first yields an explicit expression for the anisotropy tensor. Then, assuming a simple random matrix model for the spin-orbit coupling allows us to describe the fluctuation of such a tensor analytically. In the case of uniaxial anisotropy, we calculate the distribution of the anisotropy constant for a given number of electrons, and its variation upon increasing this number by one. The magnitude of the latter scales inversely with the number of atoms in the particle and is sufficient to account for the experimental data.
PACS: 73.22.-f – Electronic structure of nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals / 73.23.Hk – Coulomb blockade; single-electron tunneling / 75.75.+a – Magnetic properties of nanostructures
© EDP Sciences, 2005
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.