Dynamic pinning at a Py/Co interface measured using inductive magnetometry

Broadband FMR responses for metallic single-layer and bi-layer magnetic films with total thicknesses smaller than the microwave magnetic skin depth have been studied. Two different types of microwave transducers were used to excite and detect magnetization precession: a narrow coplanar waveguide and a wide microstrip line. Both transducers show efficient excitation of higher-order standing spin wave modes. The ratio of amplitudes of the first standing spin wave to the fundamental resonant mode is independent of frequency for single films. In contrast, we find a strong variation of the amplitudes with frequency for bi-layers and the ratio is strongly dependent on the ordering of layers with respect to a stripline transducer. Most importantly, cavity FMR measurements on the same samples show considerably weaker amplitudes for the standing spin waves. All experimental data are consistent with expected effects due to screening by eddy currents in films with thicknesses below the microwave magnetic skin depth. Finally, conditions for observing eddy current effects in different types of experiments are critically examined

Exchange anisotropy pinning of a standing spin wave mode

Standing spin waves in a thin film are used as sensitive probes of interface pinning induced by an antiferromagnet through exchange anisotropy. Using coplanar waveguide ferromagnetic resonance, pinning of the lowest energy spin wave thickness mode in Ni(80)Fe(20)/Ir(25)Mn(75) exchange biased bilayers was studied for a range of IrMn thicknesses. We show that pinning of the standing mode can be used to amplify, relative to the fundamental resonance, frequency shifts associated with exchange bias. The shifts provide a unique `fingerprint' of the exchange bias and can be interpreted in terms of an effective ferromagnetic film thickness and ferromagnet/antiferromagnet interface anisotropy. Thermal effects are studied for ultra-thin antiferromagnetic Ir(25)Mn(75) thicknesses, and the onset of bias is correlated with changes in the pinning fields. The pinning strength magnitude is found to grow with cooling of the sample, while the effective ferromagnetic film thickness simultaneously decreases. These results suggest that exchange bias involves some deformation of magnetic order in the interface region.Comment: 7 pages, 7 figure

Implementation of variable frequency current meter by means of microcontroller

The article describes the stages of development of a variable-frequency current meter using a microprocessor based on STM32 for measurement tasks and subsequent analysis of the output current of the frequency converter.В статье описываются этапы разработки измерителя тока переменной частоты средствами микропроцессора на базе STM32 для задач измерения и последующего анализа тока на выходе преобразователя частоты

SEISMIC MONITORING OF THE COAL MINING AREA ON SAKHALIN ISLAND USING TEMPORARY NETWORKS OF THE FRS GS RAS

In April – May 2021, in the Khabarovsk Territory and Sakhalin Region in the Far East Federal District of the Russian Federation, the Federal Research Center "Geophysical Survey RAS" deployed temporary networks as a part of Large-Scale Research Facilities – continuous seismic monitoring of the Russian Federation, adjacent areas and the world. The deployment of new stations provided a reliable integration of real-time seismic data into a centralized monitoring system for the Sakhalin Region.The seismic study has been performed in the Uglegorsk District, Sakhalin Region, where the Solntsevsky brown coal deposit – the most potential on the island – is located. There were presented the data on seismic events of different origin recorded since the stations had been brought into service. Emphasis has been placed on considerable improvements in epicenter location accuracy and enhancing possibilities of determining earthquakes and industrial explosions. There are shown the results of monitoring for earthquake mechanism studies. The monitoring system that is currently available allows recording the representative earthquake events with ML≥0.5 in the immediate vicinity of coal mines, thus providing the possibility of improving control of blasting work and of weak and potential induced seismicity caused by multiple anthropogenic impacts on subsoil

Micro-relief and roughness of the surface of the profiled sulfocation-exchange membrane after its contact with phenylalanine solution

The work was conducted under financial support of RFBR (project N 18-08-01260)

The use of SSR-markers in rice breeding for resistance to blast and submergence tolerance

Received: March 16th, 2022 ; Accepted: July 20th, 2022 ; Published: September 6th, 2022 ; Correspondence: [email protected] identification of effective specialized DNA markers providing the clear control of target locus inheritance by the trait of submergence tolerance has been conducted. Among the studied set of microsatellite markers, two the most informative SSR-markers - RM 7481, PrC3 showed high efficiency in detecting intraspecific polymorphism of rice varieties and lines used in the work. With the use of these markers the clear genotype marking the obtained hybrid rice plants by this trait has been conducted and it is has been verified by phenotype evaluation as a result of laboratory trials. The plant samples carrying the target gene in heterozygous and homozygous state has been selected. About 400 backcrossed self-pollinated rice lines with introgressed and pyramided resistance genes Pi-1, Pi-2, Pi-33, Pi-ta, Pi-b to Pyricularia oryzae Cav. were obtained within the frameworks of program to develop genetic rice sources resistant to blast. The conducted testing for resistance to blast and the assessment by economically valuable traits have allowed to select the prospective rice samples. The plant samples of F2 and BC1F1 generations with combination of resistance to blast genes (Pi) and submergence tolerance gene (Sub1A) in homozygous and heterozygous state that is confirmed be the results of analysis of their DNA have been obtained. The obtained hybrid plants are being tested in breeding nurseries for a complex of economically valuable traits. The best plants will be selected and send to State Variety Testing system. Their involving in rice industry will reduce the use of plant protection chemicals against diseases and weeds, thereby increasing the ecology status of the rice industry

Direct Hopf Bifurcation in Parametric Resonance of Hybridized Waves

We study parametric resonance of interacting waves having the same wave vector and frequency. In addition to the well-known period-doubling instability we show that under certain conditions the instability is caused by a Hopf bifurcation leading to quasiperiodic traveling waves. It occurs, for example, if the group velocities of both waves have different signs and the damping is weak. The dynamics above the threshold is briefly discussed. Examples concerning ferromagnetic spin waves and surface waves of ferro fluids are discussed.Comment: Appears in Phys. Rev. Lett., RevTeX file and three postscript figures. Packaged using the 'uufiles' utility, 33 k

Study of strong photon-magnon coupling in a YIG-film split-ring resonant system

By using the stripline Microwave Vector Network Analyzer Ferromagnetic Resonance and Pulsed Inductive Microwave Magnetometry spectroscopy techniques, we study a strong coupling regime of magnons to microwave photons in the planar geometry of a lithographically formed split-ring resonator (SRR) loaded by a single-crystal epitaxial yttrium-iron garnet (YIG) film. Strong anti-crossing of the photon modes of SRR and of the magnon modes of the YIG film is observed in the applied-magnetic-field resolved measurements. The coupling strength extracted from the experimental data reaches 9 percent at 3 GHz. Theoretically, we propose an equivalent circuit model of an SRR loaded by a magnetic film. This model follows from the results of our numerical simulations of the microwave field structure of the SRR and of the magnetization dynamics in the YIG film driven by the microwave currents in the SRR. The equivalent circuit model is in good agreement with the experiment. It provides a simple physical explanation of the process of mode anti-crossing. Our findings are important for future applications in microwave quantum photonic devices as well as in magnetically tunable metamaterials exploiting the strong coupling of magnons to microwave photons