New type of biosensor based on magnetic nanoparticle detection

A new type of biosensor has been developed based on detection of nanosized superparamagnetic particles that serve as labels in bioreactions. The method is based on non-linear magnetic material detection by a magnetic field having components at two frequencies f₁ and f₂. The response is measured at the combinatorial frequencies f_i=mf₁+nf₂, where m and n are integers, e.g., f_i=f₁±2f₂. Several highly sensitive readers of superparamagnetic particles have been designed and used for development of various formats of immunoassays, including those compatible with immunoconcentration and magnetic enrichment of antigens.     

Magnetostatic Energy of Domain Walls in Uniaxial Films of Finite Sizes

Physics of the Solid State - The solution to the problem of calculating the magnetostatic interaction energy of domain walls in uniaxial magnetics with a uniform magnetization distribution inside...     

Highly sensitive room-temperature method of non-invasive in vivo detection of magnetic nanoparticles

Methods of non-invasive in vivo quantification of magnetic nanoparticles (MP) have been proposed and realized. The methods are based on non-linear MP magnetization at two frequencies and measuring the response at combinatorial frequencies. The first method is developed for real-time study of MP dynamics and their clearance from the blood system of animals. High sensitivity of 3 ng of Fe₃O₄ in 0.1 ml was achieved for MP detection in mice tail veins. The second technique is proposed for MP detection inside animal tissues by an external probe. The proposed methods could essentially widen capabilities of biomedical research which involves magnetic nanoparticles.     

Bose—Einstein Condensation and Spin Superfluidity of Magnons in a Perpendicularly Magnetized Yttrium Iron Garnet Film

JETP Letters - The formation of a Bose—Einstein condensate of magnons in a perpendicularly magnetized iron yttrium garnet film under radio-frequency pumping in a stripline has been studied...     

Local probing of magnetic films by optical excitation of magnetostatic waves

Excitation of volume and surface magnetostatic spin waves in ferrite garnet films by circularly polarized laser pulses utilizing to the inverse magnetooptical Faraday effect has been studied experimentally. The region of excitation of the magnetostatic spin waves is determined by the diameter of the laser beam (～10 μm). At the same time, the characteristic propagation length of the modes is 30 μm. A method of finding the local characteristics of a magnetic film, in particular, the cubic and uniaxial anisotropy constants, based on the analysis of the azimuthal-angle dependence of the spectrum of the magnetostatic spin waves has been proposed.     

Features of the Interaction of a Magnon Bose—Einstein Condensate with Acoustic Modes in Yttrium Iron Garnet Films

JETP Letters - The interaction of a magnon Bose—Einstein condensate (mBEC) in a perpendicularly magnetized yttrium iron garnet film with high-order acoustic modes appearing at the sizes of an...     

Long-Lived Induction Signal in Yttrium Iron Garnet

JETP Letters - The results of the experiments on an yttrium iron garnet film have been reported, demonstrating two types of long-lived free induction signals. The first type corresponds well to...     

Magnetoelastic Coupling Modulation at Ferromagnetic Resonance in Garnet Ferrite Films

Technical Physics - Low-field ferromagnetic resonance in garnet ferrite epitaxial films of different composition with easy-plane anisotropy has been investigated. In ferromagnetic resonance spectra...     

Ferromagnetic Resonance and Elastic Vibrations in Epitaxial Yttrium Iron Garnet Films

Journal of Experimental and Theoretical Physics - The ferromagnetic resonance (FMR) spectra of epitaxial yttrium iron garnet films are experimentally studied. The field dependences of the FR...