Abstract
Amorphous and nanocrystalline (Fe1–xNix)81Nb7B12 (x = 0, 0.25, 0.5, 0.75) alloys were measured by M?ssbauer spectrometry in the weak external magnetic field of 0.5 T. From structural analyses, ferromagnetic bcc-FeNi and fcc-FeNi and paramagnetic (Fe-Ni)23B6 phases were identified in the annealed samples. It was shown that in the external magnetic field the intensities of the 2nd and the 5th lines (A23 parameter) are the most sensitive M?ssbauer parameters. Rather small changes were observed in the values of internal magnetic field. Our results showed that the amorphous precursor is more sensitive to the influence of external magnetic field than the nanocrystalline alloy. All spectra of amorphous precursor showed the increase of A23 parameter and decrease of internal magnetic field values of about 1 T (±0.5 T) under influence of external magnetic field. In the case of nanocrystalline samples the tendency for the values of internal magnetic field is similar but the effect is not so pronounced. The measurements confirmed that even weak external magnetic field affected orientation of the net magnetic moments. Our results indicate that effect of the external magnetic field is stronger in the case of amorphous samples due to their disordered structure.
Highlights
Nanocrystalline alloys rich in Fe prepared from amorphous precursors by crystallization represent an important part of soft magnetic materials
Our results showed that the amorphous precursor is more sensitive to the influence of external magnetic field than the nanocrystalline alloy
All spectra of amorphous precursor showed the increase of A23 parameter and decrease of internal magnetic field values of about 1 T (±0.5 T) under influence of external magnetic field
Summary
Nanocrystalline alloys rich in Fe prepared from amorphous precursors by crystallization represent an important part of soft magnetic materials. Alloys with crystallite sizes less than 100 nm have attracted attention due to some of their magnetic properties such as effective permeability and saturation magnetic flux density [5,6]. These properties indicate that these materials may have application in magnetic parts and devices such as inductors, low and high energy frequency transformers, alternating current machines, motors, generators, transducers, sensors and actuators [7,8]. In the present work we studied the influence of the weak external magnetic field on the magnetic microstructure of nanocrystalline (Fe1–xNix)81Nb7B12 (x = 0, 0.25, 0.5, 0.75) alloys and their amorphous precursors
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