Laboratory of Magnetic Materials (No. 06)

Head of the Laboratory – Corresponding Member of the NASU, Prof. Boris Ivanov

History of the laboratory

Laboratory 06 has existed at the Institute of Magnetism (IMag) since 2007. This was a time of rapid development and formation in the nanophysics of magnets. At that time, it became clear that topologically nontrivial inhomogeneous magnetization states (solitons) in magnets, such as domain walls, magnetic vortices, and many others, are natural nanoscale objects and that they can be used in various high-density information recording and processing systems. Furthermore, the development of femtomagnetism – a new field in physics of magnets using of femtosecond laser pulses to excite and analyze spin dynamics – demonstrated the high potential of antiferromagnets for achieving ultrafast (on the picosecond time scale) spin dynamics and a corresponding increase (in tens-hundreds times) in the performance of magnetic electronic systems.

From the very beginning, the laboratory's goal has been the advanced development of the theory of spin dynamics of nanoobjects, including ultrafast spin dynamics, to stimulate experimental research. High-priority results were obtained in these areas during the laboratory's early years. The excitation of the precession of a magnetic vortex in a magnetic nanoparticle by a spin current was predicted for the first-time (2007). This phenomenon was subsequently observed by many experimental groups; now it is considered as a promising avenue for creating a nanoscale microwave generator. A new inertial mechanism for the spin reorientation in antiferromagnets under the action of a femtosecond laser pulse was proposed and realized experimentally for holmium orthoferrite; it realize the fastest spin reorientation mechanism in magnetic particles (2009). A theory of longitudinal spin reorientation of ferrimagnet sublattices upon ultrafast heating with a femtosecond pulse was developed (joint publications with experimental data for the GdFeCo alloy in 2012). A scheme of antiferromagnetic nanogenerator with spin current pumping working in the terahertz range was proposed (2017).

Research Activity

The main goals of the laboratory are the theoretical study of dynamic solitons of various types for real magnetic materials with complex magnetic structures, their quantum properties and ultrafast spin dynamics, as well as the analysis of the possibility of using these effects to create compact and energy-efficient systems for recording and processing information as well as nanogenerators in the terahertz frequency ange.

Main current research directions:

– Analysis of the dynamics of vortex-type solitons and Bloch lines in antiferromagnets, which allow the existence of weak noncollinearity of sublattices (in modern terminology, altermagnets);
– Study of the excitation mechanisms of ultrafast (with a speed of more than 10 km/s) spin wave pulses in antiferromagnets;
– Search for mechanisms of spin reorientation of sublattices spins for antiferromagnets under the action of rapid heating;
– Study of nonlinear spin dynamics of antiferromagnets with broken symmetry of the spin system with respect to spatial inversion (so-called PT-antiferromagnets).

Principal research projects

Ongoing projects:
– In-house project (fundamental) No. 0122U001845 “Kinetic, thermodynamic and magnetodynamic effects in multiparticle, quantum and mesoscopic systems”.

Acomplished projects:
– Grant of National Research Foundation of Ukraine No. 2020.02/0261 “Development of physical foundations of magnetic nanoelectronics”, 2020-2023.

Selected scientific results

– A high-frequency spin Hall generator and a spin-wave emitter based on the instability effect of domain wall dynamics in nearly compensated ferrimagnets is proposed [read more]

Laboratory staff:

Head of the Laboratory, Corresponding Member of the NASU, Prof. Boris Ivanov
Leading Researcher, D. Sc. Elena Tartakovskaya
Leading Researcher, D. Sc. Valerii Orel
Leading Researcher, Corresponding Member of the NASU, Prof. Oleksiy Kolezhuk
Senior Researcher, Dr. Vadim Kireev
Junior Researcher, Dr. Artem Bondarenko
Junior Researcher Lidiia Ushii
PhD student Yaroslav Velyhotskyi