Microstructure and hyperfine interactions of the nanocrystalline alloys: Mössbauer effect temperature measurements

Abstract

Mössbauer spectrometry, magnetization measurements and differential scanning calorimetry were used to investigate the microstructure and hyperfine interactions in the nanocrystalline alloy obtained by heat treatment of the original amorphous precursor at the temperature of for 1 hour. transmission Mössbauer spectra were taken in the temperature range 5-475 K without and with external magnetic field oriented parallel and perpendicular to the ribbon-shaped sample. The as-quenched state of the alloy was also investigated. The Mössbauer effect measurements confirmed the presence of -Fe phase upon nanocrystallization. Magnetic states of Fe atoms in amorphous and interfacial regions are studied via distributions of hyperfine fields.

Mossbauer-Spectroscopy Characterization of Nanostructured Magnetic Materials

“…Mössbauer spectroscopy has been shown to be a powerful tool for magnetic and structural characterization of nanostructured magnetic alloys based on iron AKSENOVA, CHUEV [4][5][6][7][8][9][10][11][12][13]. The materials consist of nanoparticles in the form of α -Fe crystal grains embedded in an amorphous matrix.…”

“…An advantage of this approach is that it does not presuppose any knowledge of the distributions to be identified. It was instrumental in reconstructing the temperature variation of the H hf distribution for the nanoparticles and the matrix; furthermore, interface zones were thus discovered between the two phases [4][5][6]. However, the common approach gives little or no quantitative information about the individual contributions of the phases to the resulting distribution of hyperfine-structure parameters.…”

“…1), a phenomenon observed in half of studies dealing with nanostructured magnetic alloys [4][5][6][7][8][9][10][11][12][13] or with other superparamagnetic-particle systems [17][18][19][20][21][22][23]. A qualitative explanation free from a continuous H hf distribution was first proposed within the GTLR model [24,25].…”

“…For a nanoscale particle, KV/k B is of order 100 K, so that all the states with arbitrary orientations of the magnetic moment relative to the axis of anisotropy are populated even at room temperature. Modern technology enables one to produce such particles [4][5][6][7][8][9][10][11][12][13].…”

“…(5). The sense of precession for the magnetic moment is determined by the sign of the constant K. If K > 0, implying an easiest magnetic axis, then Ω < 0 (left-hand precession).…”