Modern microelectronic devices based on the layered spin-valve structures are characterized by low power consumption, high reliability and wide temperature range. The study of the spin valve modes and the investigation of the possibilities of controlling these modes are of practical interest. In the work the spin valve modes operation, which are the base for magnetoresistive random-access memory MRAM, a binary stochastic neuron p-bit and a variety of the spin-transfer nano-oscillators STNOs, have been considered. For this purpose, a mathematical model of a spin valve with longitudinal anisotropy, placed in a magnetic field perpendicular to the axis of anisotropy and parallel to the plane of the layers has been constructed. A system of equations, describing the dynamics of the magnetization vector of the free layer of the spin valve has been obtained. The qualitative analysis of this system has enabled us to determine the equilibrium state of the free layer magnetization for the spin-valve structure. Based on the bifurcation analysis of the dynamic system of equations the conditions for changing the type of singular points of the system have been determined. The study on the dynamics of the magnetization vector of the free layer of the spin valve has helped to identify the main modes of its work as a part of the magnetoresistive random access memory, a binary stochastic neuron, spin-transfer nano-oscillators and to determine the ranges of the current and the magnetic field corresponding to the modes. For the spin-transfer nano-oscillators, also, the frequency and amplitude characteristics have been calculated. The proposed structure with planar anisotropy, placed in the field, which is perpendicular to the anisotropy axis, from the point of view of its application as a spin-transfer nano-oscillator will be more preferable than the structure with the field applied in parallel to anisotropy axis.
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