METHOD OF CONTROLLING MAGNETOELASTIC COUPLING USING COHERENT OPTICAL LASER RADIATION IN FERRITE-GARNET EPITAXIAL FILMS Russian patent published in 2022 - IPC C30B29/28 G01R33/12 G01R33/20 C30B19/02 C30B19/12 

FIELD: physics.

SUBSTANCE: invention relates to the field of sensorics and microwave technology, in particular to the creation of controlled magnetic field sensors, filters, modulators and microwave radiation routers, optically controlled logic elements, signal converters, the working material of which is epitaxial films of ferrite-garnets with tunable properties due to control of magnetoelastic coupling in a monocrystal by means of coherent optical (laser) radiation. Method of controlling magnetoelastic coupling in monocrystalline magnetic epitaxial films of cation-substituted ferrite garnets 1 includes installation of a sample of a film of ferrite-garnet 1 into measuring cell 2, placed in an external alternating magnetic field B, characterized by frequencies of microwave radiation, when applying external constant magnetic field B₀, wherein measuring cell 2 is connected to vector circuit analyzer 3 for interaction of microwave radiation with spin system of magnetic film for excitation and registration of ferromagnetic resonance (FMR), modulated by the effect caused by magnetoelastic coupling, and characterized by FMR spectra based on the frequency dependence of the modulus of the complex transmission coefficient S₂₁, wherein the outer surface of ferrite-garnet film 1 is irradiated through the made hole in measuring cell 1 with plane-polarized optical laser monochromatic coherent radiation 6 with wavelength of 680 nm and a power density in the range of not more than 10⁴ W/m² with a change in the frequency range of oscillations of the alternating magnetic field B within 200–1,500 MHz, constant magnetic field B₀ in range of 5–50 Oe, thereby changing the modulation depth of the FMR spectra due to the change in magnetoelastic coupling induced by optical laser radiation. Invention uses principle of photoinduced change of magnetic anisotropy value, which leads to change in magnetoelastic coupling in monocrystalline epitaxial films of ferrite garnets. Change in the magnetoelastic coupling value affects the efficiency of spin excitation of acoustic (phonon) modes and, as a result, the value of modulation of the ferromagnetic resonance spectrum.

EFFECT: increased efficiency and speed of dynamic opto-magnetic control of magnetoelastic coupling in cation-substituted monocrystalline epitaxial films of ferrite garnets, as well as the possibility of combining on one solid-state crystal three interconnected different external factors of action and transmission of signals, such as magnetic field, microwave radiation and optical radiation.

1 cl, 2 dwg, 1 ex