Twengström, M;
Bovo, L;
Gingras, MJP;
Bramwell, ST;
Henelius, P;
(2017)
Microscopic aspects of magnetic lattice demagnetizing factors.
Physical Review Materials
, 1
, Article 044406. 10.1103/PhysRevMaterials.1.044406.
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Abstract
The demagnetizing factor N is of both conceptual interest and practical importance. Considering localized magnetic moments on a lattice, we show that for nonellipsoidal samples, N depends on the spin dimensionality (Ising, XY, or Heisenberg) and orientation, as well as the sample shape and susceptibility. The generality of this result is demonstrated by means of a recursive analytic calculation as well as detailed Monte Carlo simulations of realistic model spin Hamiltonians. As an important check and application, we also make an accurate experimental determination of N for a representative collective paramagnet (i.e., the Dy_2Ti_2O_7 spin ice compound) and show that the temperature dependence of the experimentally determined N agrees closely with our theoretical calculations. Our conclusion is that the well-established practice of approximating the true sample shape with “corresponding ellipsoids” for systems with long-range interactions will in many cases overlook important effects stemming from the microscopic aspects of the system under consideration.
| Type: | Article |
|---|---|
| Title: | Microscopic aspects of magnetic lattice demagnetizing factors |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1103/PhysRevMaterials.1.044406 |
| Publisher version: | https://doi.org/10.1103/PhysRevMaterials.1.044406 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Condensed matter & Material physics, Statistical physics, Dipolar interaction, Magnetic susceptibility, Magnetism, Magnetic insulators, Finite-size scaling, Ising model, Mean field theory, Monte Carlo methods, Spin lattice models, Susceptibility measurements |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy UCL > Provost and Vice Provost Offices > VP: Innovation and Enterprise UCL > Provost and Vice Provost Offices > VP: Innovation and Enterprise > Business and Innovation Partnerships |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/1539808 |
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