P.A. Popov – Engineer,
Kotel’nikov Institute of Radio Engineering and Electronics of RAS (Moscow)
E-mail: paavali.popov@gmail.com
A.R. Safin – Associate Professor, Senior Research Scientist,
Kotel’nikov Institute of Radio Engineering and Electronics of RAS (Moscow)
E-mail: arsafin@gmail.com
S.A. Nikitov – Professor, Director,
Kotel’nikov Institute of Radio Engineering and Electronics of RAS (Moscow)
E-mail: nikitov@cplire.ru
Problem formulating. Nowadays there is a problem of lack of methods and devices for generation and receiving signals in the frequency range of 0.1–10 THz in the fields of experimental and applied physics. One of the solutions to this problem may be provided by the spintronic devices. In one of the recent works it has been shown that a two-layer structure of platinum and antiferromagnetic layers can be used to generate terahertz signals driven by the electric current in platinum, which causes magnetization autooscillation in antiferromagnet via spin transfer torque (STT). However, the current densities of 108–109 A/cm2 necessary for the start of generation represent a certain problem for application in real devices. One of the ways to overcome this limitation is to consider the dynamics of magnetization in antiferromagnet taking into account the magnetoelastic interaction.
Goal. To describe the magnetic dynamics in a multilayer system of platinum, antiferromagnetic and piezoelectric layers, taking into account the STT and the magnetoelastic interaction; develop a physical model and derive the equations describing the magnetic dynamics.
Result. Equations describing the dynamics of magnetization in the antiferromagnetic layer were derived taking into account the contribution of electric current in the platinum layer, static mechanical stress in the antiferromagnetic layer and deformation caused by an electric field in the piezoelectric layer. Two solutions describing damped oscillations and autooscillations of magnetization have been found; the conditions for realization of these solutions and the dependences of frequency and amplitude of oscillations on the value of electric current in platinum and electric field in piezoelectric layer have been found. Graphic dependencies for material parameters of antiferromagnetic NiO and piezoelectric PZT-5H were obtained.
Practical meaning. The results indicate the possibility of controlling the oscillations parameters in the system by means of electric current and electric field, allowing to adjust the frequency, amplitude and threshold conditions for different types of oscillations. The system in a state of damped oscillations can be used for resonance signal absorption and thus used as a narrowband detector; the system in a state of autooscillations can be used to generate signals.
- Khymyn R., Lisenkov I., Tiberkevich V., Ivanov B.A., Slavin A. Antiferromagnetic THz-frequency Josephson-like Oscillator Driven by Spin Current. Scientific reports. 2017. № 7. Р. 43705.
- Popov P., Safin A., Nikitov S. Influence of elastic stress on THz-frequency oscillations in antiferromagnets. 2019 International Congress on Ultrasonics. 2019. Р. 58.
- Popov P.A., Safin A.R., Nikitov S.A. Thz-frequency oscillations in antiferromagnets with magnetoelastic coupling. VII Euro-Asian Symposium «Trends in MAGnetism» EASTMAG–2019. 2019. V. 1. Р. 171−172.