Change search
ReferencesLink to record
Permanent link

Direct link
Multidimensional instability and dynamics of spin-avalanches in crystals of nanomagnets
Umeå University, Faculty of Science and Technology, Department of Physics.
Umeå University, Faculty of Science and Technology, Department of Physics.ORCID iD: 0000-0003-3096-1972
Umeå University, Faculty of Science and Technology, Department of Physics. Department of Applied Physics, Chalmers University of Technology, Göteborg, Sweden.
Umeå University, Faculty of Science and Technology, Department of Physics.
2014 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 113, no 21, 217206Article in journal (Refereed) Published
Abstract [en]

We obtain a fundamental instability of the magnetization-switching fronts in superparamagnetic and ferromagnetic materials such as crystals of nanomagnets, ferromagnetic nanowires, and systems of quantum dots with large spin. We develop the instability theory for both linear and nonlinear stages. By using numerical simulations we investigate the instability properties focusing on spin avalanches in crystals of nanomagnets. The instability distorts spontaneously the fronts and leads to a complex multidimensional front dynamics. We show that the instability has a universal physical nature, with a deep relationship to a wide variety of physical systems, such as the Darrieus-Landau instability of deflagration fronts in combustion, inertial confinement fusion, and thermonuclear supernovae, and the instability of doping fronts in organic semiconductors.

Place, publisher, year, edition, pages
American Physical Society , 2014. Vol. 113, no 21, 217206
National Category
Condensed Matter Physics
URN: urn:nbn:se:umu:diva-96684DOI: 10.1103/PhysRevLett.113.217206ISI: 000345745800012PubMedID: 25479521OAI: diva2:766171
Swedish Research Council
Available from: 2014-11-26 Created: 2014-11-26 Last updated: 2016-08-12Bibliographically approved
In thesis
1. Magnetic deflagration and detonation in crystals of nanomagnets
Open this publication in new window or tab >>Magnetic deflagration and detonation in crystals of nanomagnets
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

In this thesis we cover the dynamics of the macro magnetic transformations (spin avalanches) in crystals of molecular nanomagnets, also known as magnetic deflagration and detonation.

Taking a single-molecule Hamiltonian, we calculate the dependence of Zeeman energy and the activation energy as a function of an external magnetic field at different angles relative to the easy axis of the crystal. Using quantum mechanical calculations, we show that the energy levels of the molecule exhibit complex behavior in presence of a transverse component of the magnetic field. For an arbitrarily aligned magnetic field, the energy levels do not arrange in a simple "double-well" manner. We extend existing theoretical models by generalizing the Zeeman energy for a wide range of magnetic fields and its different orientations.

We obtain a new type of front instability in magnetization-switching media. Due to the dipole-dipole interaction between the molecules magnetic instability results to the front banding and change in the front propagation velocity. The magnetic instability has a universal physical nature similar to the Darrieus-Landau instability. The instability growth rate and the cutoff length are calculated for the spin avalanches in the crystals of nanomagnets.

Finally, we investigate the internal structure of the magnetic detonation front. We calculate the continuous shock profile using the transport processes of the crystal such as thermal conduction and volume viscosity. Such an approach can be applied to any weak shock wave in solids. Zero volume viscosity leads to an isothermal jump, i.e., the temperature changes continuously while the pressure and the density experience discontinuity. The analysis has shown that the volume viscosity plays a major role in the formation of the detonation front.

Place, publisher, year, edition, pages
Umeå: Umeå University, 2016. 40 p.
Nanomagnets, magnetic deflagration, front instability, Zeeman energy, magnetic instability, magnetic detonation, weak detonation
National Category
Physical Sciences
Research subject
Physics Of Matter
urn:nbn:se:umu:diva-124445 (URN)978-91-7601-534-6 (ISBN)
Public defence
2016-09-05, MC413, MIT-huset, Umeå, 13:00 (English)
Available from: 2016-08-15 Created: 2016-08-11 Last updated: 2016-08-15Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textPubMed

Search in DiVA

By author/editor
Jukimenko, OlexyDion, ClaudeMarklund, MattiasBychkov, Vitaly
By organisation
Department of Physics
In the same journal
Physical Review Letters
Condensed Matter Physics

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 168 hits
ReferencesLink to record
Permanent link

Direct link