Izvestiya VUZ. Applied Nonlinear Dynamics

The purpose of this work is to obtain an expression for the discriminative characteristic of the spin wave phase comparator, which is the dependence of the amplitude of the output voltage on the phase difference of the exciting microwave oscillations. This comparator is based on an antiferromagnetic film and three microstrip antennas, two of which receive microwave signals, the phases of which need to be compared, and the output voltage is removed from the third. In addition, this paper examines the behavior of the discriminative characteristic for various positions of the receiving antenna. Methods. To describe an antiferromagnetic waveguide, an equivalent electrical circuit based on concentrated elements was compiled. The radio engineering model was considered in the form of active and reactive resistances of spin wave excitation and reception antennas, as well as active and reactive resistances characterizing the propagation of spin waves in an antiferromagnetic film. The components of the magnetic susceptibility tensor of an antiferromagnet are derived from the Landau-Lifshitz-Hilbert equations, which made it possible to describe the relationship between the electric and magnetic systems. The theoretical results were confirmed using micromagnetic modeling. Results. The principle of operation of a spin wave phase comparator based on an antiferromagnetic film is described. Using an equivalent electrical circuit, the main characteristic of the comparator is obtained - the dependence of the amplitude of the output voltage at the receiving antenna on the phase difference of the exciting microwave signals. Also, the dependence of the amplitude of the output voltage on the position of the receiving antenna is constructed. Micromagnetic modeling was carried out to verify the theoretically obtained results. Conclusion. In this paper, an expression is obtained for the discriminatory characteristic of an antiferromagnetic film-based comparator with an arbitrary location of the receiving antenna. It is shown that the discriminative characteristic depends on the spatial location of the receiving antenna. The highest efficiency of the comparator is achieved if the detector is located in the middle between the exciting antennas.

The purpose of this work is to experimentally investigate the spin Hall effect magnetoresistance (SHE) and, using the inverse spin Hall effect (ISHE), spin pumping by traveling surface magnetostatic waves (MSSW) in the Pt(4 nm)/YIG(600 nm) microstructure based on a polycrystalline YIG film obtained by ion sputtering on a SiO2(100 nm)/Si substrate. The measurement results are compared with the case of the Pt(4 nm)/YIG(900 nm) structure obtained on the basis of an epitaxial YIG film. Methods. The experiments were performed with a MSSW delay line layout based on the YIG/Pt microstructure. The amplitudefrequency characteristics of the transmission and reflection coefficients and the frequency dependences of the EMF V(f) induced in the Pt element due to the ISHE were studied. Results. It is shown that the values of the SHE in the structures are of the same order f magnitude, which reflects the proximity of the saturation magnetization of the samples of 1750 G and 1432 G. At the same time, the values of the EMF generated in the structures during the propagation of the MSSWs due to the inverse spin Hall effect are almost two orders of magnitude higher for the structure based on the epitaxial YIG film. This discrepancy in the EMF values is associated with the low microstructural perfection of the YIG (600 nm)/SiO2 (100 nm)/Si film due to growth defects, which is manifested in the FMR linewidth ΔH ≈ 56 Oe, more than 40 times higher than the ∆H value in the epitaxial YIG film. Large values of ΔH reduce the amplitude and increase the attenuation of the excited MSSWs. Conclusion. The feasibility of spin pumping in a YIG/Pt structure fabricated on a SiO2/Si semiconductor substrate is demonstrated. The results are of interest for the development of energy-efficient components based on magnonic spintronics principles.