Магнитный импеданс пленочных наноструктур для оценки полей рассеяния микрочастиц магнитных композитов

Longitudinal giant magnetoimpedance effect of [Fe21Ni79/Cu]5/Cu/[Fe21Ni79/Cu]5 film element was investigated depends on stray magnetic field of epoxy magnetic composite with 30 % weight concentration of iron oxide magnetic microparticles. Configuration of an experiment was a model of thrombus detection in a blood vessel. Stray magnetic field was varied by movement of a magnetic composite above the element perpendicular to the long side. Composite was either magnetized or not to the state of remanence. As the magnetic composite approaches the GMI element, MI ratio curves are smoothed and shifted along the field axis and maximum value of the MI ratio decreases. Magnetic properties of magnetic composite and film element were investigated as well.

Magnetic Field Sensor Using Asymmetric Giant Magnetoimpedance Effect Created by Micro Magnets

A magnetic field sensor was developed using asymmetric giant magnetoimpedance (AGMI) effect. Amorphous ferromagnetic (Fe0.06Co0.94) 72.5Si12.5B15 wires were used in this study. The 2 cm long wire showed about 88 % and the 7 cm long wire showed about 197 % giant magnetoimpedance effect. When two micro magnets were placed 1 cm away from the ends of the wire, a distortion in two peak shapes of the GMI curve was observed and asymmetry was created by micro magnets and 7 cm long wire showed about 148 % AGMI effect. A simple and a new approach was designed to develop a magnetic field sensor, in the design circuit two signal generators were used to arrange linearity and dc offset in the output signal. The circuit output showed good linearity and zero hysteresis at ±250 A/m and ± 50 A/m magnetic field regions for 2cm wires long and 7 cm wires long, respectively.

Магнитные наночастицы, полученные электрофизическими методами: фокус на биомедицинские приложения

This work describes the possibility of fabrication of the large batches of magnetic nanoparticles using electrophysical methods of electric explosion of the wire, laser target evaporation and spark discharge. Bioapplications of nanoparticles require the production of magnetic materials in the form of stabilized aqueous suspensions or hydrogels with magnetic fillers; therefore, some details of the synthesis of these materials and their certification are discussed. The peculiarities of interaction of magnetic nanoparticles with biological systems, the problem of biocompatibility, the possibility of using ferrogel substrates for the needs of cell technologies and regenerative medicine, as well as implication of biomimetics in the development of magnetic biosensors are considered. The results of the analysis of a number of different biological experiments carried out with suspensions of various types, obtained based on the same batch of MNPs are presented. An analysis of examples of magnetic biodetection and existing theoretical approaches will make it possible to assess the prospects of this scientific direction for the creation of highly sensitive thin film sensors based on the giant magnetoimpedance effect for biomedical applications