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Transverse magnetic anisotropy has been induced in the Fe 14.7 Co 58.8 Cu 1 Nb 3 Si 13.5 B 9 and Fe 13.8 Co 65 Cu 0.6 Nb 2.6 Si 9 B 9 amorphous ribbons by annealing under an external magnetic field. This anisotropy plays a predominant role, compared to magneto-crystalline and magneto-elastic anisotropies, in forming the magnetic properties and shaping the hysteresis loop. The effect of temperature and time of annealing on the induced magnetic anisotropy and magnetic properties (magnetic permeability, coercivity and power losses) in both alloys was investigated. Under this work, measurements of frequency dependence of the real and imaginary parts of magnetic permeability were made within a frequency range up to 110 MHz. It was found that as a result of magnetic field annealing the Snoek limit increases in both alloys compared to the Co-free Finemet.

This work was aimed at investigating the FeNbCuSiB and FeNiMoB type alloys exhibiting relatively high saturation magnetostriction after suitable heat treatment, which makes them suitable for application in force sensors. Samples of both alloys were prepared in a form of toroidal cores wound from amorphous ribbons obtained by melt-spinning, and then the cores were annealed under longitudinal and transverse magnetic field. An effect of the induced magnetic anisotropy and of the applied compressive stresses on the dynamic magnetic properties of both alloys within a frequency range from 50 Hz to 50 kHz was studied.

The influence of partial substitution of Fe by Co in Fe 7 8 . 8 - x Co x Cu 0 . 6 Nb 2 . 6 Si 9 B 9 alloy (x = 0, 20, 40, 60) on soft magnetic properties has been investigated for application at high frequency range. The affect of the value of transverse magnetic field and duration of the annealing on the induced magnetic anisotropy were examined. The magnetic properties of FeCoCuNbSiB nanocrystalline alloys were measured in dependence on magnetizing field frequency (10 Hz - 300 kHz). The transverse magnetic anisotropy induced in the Fe 7 8 . 8 - x Co x Cu 0 . 6 Nb 2 . 6 Si 9 B 9 alloys improves significantly their performance during operation at high-frequency fields and makes them very attractive material suitable for application in power electronic devices.

Magnetic properties of the cores made from the (Fe1−xCox)73.5Cu1Nb3Si13.5B9 alloy (x=0.136, 0.272, 0.408, 0.544, and 0.680) were investigated within frequency range of 0.05–50 kHz and at the environment temperatures ranging from 298 to 643 K. It was found that the alloy with Co content corresponding to x=0.136 has the best high-temperature and high-frequency magnetic properties in comparison with the other alloys investigated in this work.

Dynamic magnetic properties of a new FeCoNbBP alloy were measured under four types of voltage excitation: sinusoidal, triangular, square and ramp. Samples were prepared in a form of toroidal cores wound from melt-spun amorphous ribbons and subjected to suitable thermo-magnetic treatment in a transverse magnetic field. The measurements were carried out within a frequency range from 1 to 50 kHz using a computerized hysteresis loop tracer fitted with the function generator enabling non-sinusoidal voltage excitation. It was found that the core losses for this material clearly depend on excitation conditions and over the frequency range studied they were generally higher at triangular waveform and lower at square waveform compared to sinusoidal excitation. At the square wave voltage excitation, the differences were reaching 19%.

The research results for different stages of production of a three-phase 250 kVA distribution transformer using three-limb amorphous magnetic core have been presented. The core is made from six frames wound from 23 μm thick Metglas 2605 TCA ribbon. Magnetic characteristics for the frames and three-limb core were measured. The 250 kVA distribution transformer was manufactured.

The magnetic domain structure is a specific property of ferromagnetic materials influencing their main magnetic properties. The aim of this work was to determine a relationship between nanocrystalline and the domain structure observed by means of magneto-optic Kerr effect on the surface of the Fe14.7Co58.8Cu1Nb3Si13.5B9 and Fe13.8Co65Cu0.6Nb2.6Si9B9 toroidal cores, and the induced transverse magnetic anisotropy Ku. The transverse magnetic anisotropy was induced in the Fe14.7Co58.8Cu1Nb3Si13.5B9 and Fe13.8Co65Cu0.6Nb2.6Si9B9 amorphous cores by annealing them at the temperature of 460 °C, under an external magnetic field of 500 kA/m. It was found that the appearance of nanocrystalline phase in the Fe13.8Co65Cu0.6Nb2.6Si9B9 alloy resulted in considerable increase of the magnetic anisotropy constant to 900 J/m3 already after 40 minutes of heating, whereas the nanocrystallization process in the Fe14.7Co58.8Cu1Nb3Si13.5B9 alloy proceeded much slower (after 240 minutes of heating the content of nanocrystalline p...