Spin-photonics Laboratory

Scientific results:

• A theory of the functioning of spin-transfer devices based on antiferromagnetic dielectrics operating in the terahertz frequency range was developed. Specifically:
• It was established that the electric field in the piezoelectric layer can be used to induce magnetic anisotropy fields, alter the frequency of magnetic resonance, and change the critical current required to excite self-oscillations. This result was demonstrated using the example of the Pt/NiO/PZT-5H heterostructure.
• Models of spin current converters, emitters, and spin current valves based on antiferromagnetic dielectrics were developed. Graphical dependencies of the frequency of magnetic oscillations in the antiferromagnet were obtained for the parameters of antiferromagnetic NiO and piezoceramic PZT-5H under various external electric voltages applied to the piezoelectric material.
• It was shown that in the "canted antiferromagnet-heavy metal" heterostructure, the response of the spin system increases linearly with the amplitude of the pumping pulse at the fundamental (resonant) antiferromagnetic mode and quadratically at the second harmonic. The possibility of controlling the switching of sublattice magnetizations in an antiferromagnet with weak ferromagnetism (Dzyaloshinskii-Moriya interaction) using terahertz electromagnetic field pulses was demonstrated.
• The following scientific results were obtained during the experimental studies:
• Quasi-static magnetization reversal processes in parabolic-shaped magnetoelastic nanostrips were studied. It was shown that the symmetry of stable magnetization states in the nanostrip can be disrupted by applying a static magnetic field perpendicular to the easy axis of the ferromagnet. The experiments were conducted on 8 nm thick CoPt films. The possibility of using pulsed force nanolithography with an atomic force microscope (AFM) probe to create nanoscale regions with increased current density was investigated.
• The acoustic generation of parametric spin waves (ASWs) in bulk acoustic wave resonators containing YIG films in contact with a Pt film was experimentally observed for the first time. The detection of parametric YIG waves was carried out using the spin pumping they create and the inverse spin Hall effect (ISHE).
• The temperature-dependent dynamics of the domain wall were obtained over a temperature range that includes both the angular momentum compensation point and the magnetization compensation point in the garnet film, extending up to the Curie temperature. A sharp difference in domain wall mobility and the maximum achievable speed near these two compensation points was demonstrated. High domain wall mobility in weak applied magnetic fields was observed.
• A neuromorphic-interference computing and signal processing paradigm was developed, involving the simultaneous use of current-excited antiferromagnetic (AFM) oscillators in the terahertz range and AFM buses (AFM waveguide systems). A concept for an ultra-fast neuromorphic computing processor with optical and electrical control based on an antiferromagnetic/heavy metal (AFM/HM) heterostructure was proposed.
• Prototypes of magnonic waveguide and logic devices for neuromorphic magnonic signal processing were developed. Prototypes of magnonic waveguides and spin-wave logic devices based on domain walls were proposed, as well as methods for altering the position of domain walls.

Education and personnel occupational retraining:

• Every year we conduct a scientific seminar and workshop «Spin photonics» on the grounds of the Institute of the Institute of Radio-engineering and Electronics of the Russian Academy of Sciences.
• Employees of the Laboratory have developed and launched the following disciplines at HSE University: «Basics of magnetism» and «Nanomagnetism and spintronics» for third-year bachelor’s degree students, as well as a specialized case study in spin photonics course for bachelor’s and master’s degree students.

Cooperation:

Moscow Institute of Physics and Technology, N. G. Chernyshevsky Saratov State University, Institute for Physics of Microstructures of the Russian Academy of Sciences, Far Eastern Federal University (Russia): joint research.

We are also actively collaborating with the Research and Practice Center of the National Academy of Sciences of Belarus.