INFORMATION ABOUT PROJECT,
SUPPORTED BY RUSSIAN SCIENCE FOUNDATION

The information is prepared on the basis of data from the information-analytical system RSF, informative part is represented in the author's edition. All rights belong to the authors, the use or reprinting of materials is permitted only with the prior consent of the authors.

 

COMMON PART


Project Number23-22-00328

Project titleMagnetic frustrations of 3D artificial spin ice

Project LeadShevchenko Yuriy

AffiliationInstitute for Applied Mathematics, Far Eastern Branch, Russian Academy of Sciences,

Implementation period 2023 - 2024 

Research area 02 - PHYSICS AND SPACE SCIENCES, 02-207 - Magnetic properties and materials

KeywordsArtificial nanosystems, metamaterials, spin ice, magnetic frustrations, Monte Carlo methods, magnetism, statistical thermodynamics, high-performance computing


 

PROJECT CONTENT


Annotation
Artificial spin ice is a metamaterial consisting of islands of magnetic material stacked in such a way that the resulting structure exhibits collective magnetic properties associated with the competition of the magnetic fields of individual islands. The island is a single-domain nanoscale magnet that can interact with other islets through dipole-dipole interaction. The lattice geometry imposes configuration constraints, due to which not all pairwise interactions can be simultaneously satisfied. This phenomenon is called frustrations and systems are frustrated. The ability to fine-tune the lattice geometry allows one to improve the properties of metamaterials, such as magnetic susceptibility, anisotropy, energy barriers between similar energy configurations, etc. Most research over the past 15 years has focused on planar magnetic structures, which have many disadvantages. The most important is insufficiently dense packing. The use of bulk artificial spin ice makes it possible to achieve more consistent and stable exotic magnetic states and, therefore, denser packing of electronic devices that use spin ice effects. But it causes several difficulties both in numerical simulations and in experiments. Techniques for the production and preparation of nanoscale magnetic metamaterials are actively developing, and researchers are offering increasingly sophisticated ways to create precise samples of magnetic structures, including three-dimensional (bulk) spin ices. The possibilities of material design are limited only by the imagination of the researchers. Such tuning, as well as predicting the properties of experimental materials, is possible with using numerical experiments and computer physical modeling. But for three-dimensional systems, even the minimum system size required to simulate the desired effect is much larger than the same in two-dimensional case. There is a large variety of configurations of artificial spin ice objects, differing in both material composition and shape, and each of them has its own unique properties. Without computer modeling or experiment, it is impossible to predict these properties in advance. Hence, there is a complex and large-scale task of classifying them and determining their thermodynamic characteristics. The project proposes the search and theoretical study of the magnetic properties of three-dimensional frustrated lattice structures with the potential possibility of creating a real prototype and further application in electronic devices. The task is planned to be solved by computer modeling methods, which requires fine-tuning of existing computational methods for working with three-dimensional macrospin structures and long-range dipole-dipole interaction. The task requires creation and optimization of computational algorithms to work with spin ice objects.

Expected results
The project will propose structures of new bulk spin ice metamaterials and examine in detail their thermodynamic properties. These are three-dimensional lattices consisting of magnetic particles with the size of several tens nanometers that shows the frustration effect in the point dipole model. Improvements in nanofabrication techniques are helping to prototype materials with high accuracy, and allowing observation of new, previously unknown phenomena. With the development of technologies and experimental techniques, it became possible to realize almost any geometry and realize direct control of collective magnetic dynamics, which opened the way to a meaningful synthetic design of new exotic states, not inherent to natural materials. The obtained results can become the basis for further in-situ experiments. Possible applications of the resulting metamaterials include microelectronic devices for computing, storing and encrypting data, with the prospect of using the materials in the emerging field of unconventional computing, including non-boolean or neuromorphic computing.


 

REPORTS


Annotation of the results obtained in 2023
To calculate the system of dipoles on three-dimensional lattices with unconstrained and constrained interaction radius, the project team implemented the Metropolis algorithm as an efficient parallel c++ code. We consider a model of Ising-like point dipoles located on the edges of a simple cubic lattice. By using the developed software we obtained the temperature behaviour of heat capacity, magnetization and magnetic susceptibility in the nearest-neighbour model and the model with a limited long-range interaction radius. Three thermodynamic magnetic phases are present in the system: long-range order, short-range order, and disorder. The long-range order phase is absent in the nearest-neighbour model. The short-range order phase is characterised by a high level of entropy induced by the lattice geometry. An external magnetic field along one of the basis axes leads to the competition of order parameters in the model with a limited long-range interaction radius, and to the disappearance of residual entropy as a heat capacity peak in the nearest-neighbour model. The nonlinear dependence of the critical temperature of heat capacity on the concentration of dilution of the system by nonmagnetic vacancies in the nearest-neighbour model is shown.

 

Publications

1. Strongin V.S., Ovchinnikov P.A., Lobanova E.A., Trefilov I.V., Shevchenko Y.A. Разбавленная модель кубического спинового льда Дальневосточный математический журнал, - (year - 2024)

2. Lobanova E.A., Ovchinnikov P.A., Trefilov I.V., Strongin V.S., Shevchenko Y.A. Температурные зависимости термодинамических характеристик искусственного спинового льда на решётке Апамея ВЫЧИСЛИТЕЛЬНЫЕ ТЕХНОЛОГИИ И ПРИКЛАДНАЯ МАТЕМАТИКА Материалы II Международного семинара, С. 121-123 (year - 2023) https://doi.org/10.22250/9785934933921_121

3. Trefilov I.V., Lobanova E.A., Ovchinnicov P. A., Strongin V.S., Shevchenko Yu.A. Фазовый переход и кроссоверы системы Изинг-подобных диполей на каирской решетке ВЫЧИСЛИТЕЛЬНЫЕ ТЕХНОЛОГИИ И ПРИКЛАДНАЯ МАТЕМАТИКА Материалы II Международного семинара, C. 213-215 (year - 2023) https://doi.org/10.22250/9785934933921_213