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Engineering of the permanent magnets is important part of the modern technologies of
the gyroscopes, sensors, medical nanotechnolyies, tomography, hyperthermia, etc. Our
researches result in accurate measurements of the electrical parameters, geophysical
orientation, industry of the sensors etc. New generation of the FeCoB magnets modified
by rare-earth metals was developed in our laboratory. Initial microparticles, crystal
structure of the main magnetic phase and domain structure of the alloys are shown in
the pictures.
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| Alloys RE-TM-B based on rare-earth (RE) and transition
(TM) metals doped with boron became widely known in the 1980-ies due to the achievement
of a theoretical limit of magnetic energy (BH)max = (4πMs)2/4
(B is magnetic field induction, Н is magnetic field strength, Ms
is saturation magnetization) and exceptional magnetic characteristics providing stability
and wide applications of the magnets. Magnetic energy of 290 kJ/m3 for the
Nd2Fe14B alloys of tetragonal atomic structure exceeds all
known values. These alloys and combinations of different phases stimulated a new
branch of materials science and engineering of magnets suitable for different
applications. The analysis of magnetic properties RE-TM-B alloys provided new
fundamental knowledge on magnetism. Gradual control of atomic concentration provided
the comprehension of physical origin of magnetic anisotropy including the case of
perpendicular anisotropy important for spintronics, and intra-/interlattice exchange
interactions as well. |
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