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Search for canted spin arrangement in Er2-xTbxFe14B with Mössbauer spectroscopy

Kurzydło P. M., Bogacz B. F., Pędziwiatr A. T., Oleszak D., Przewoźnik J.

Nukleonika

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2015

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Vol. 60, No. 1

93--96

EN

The materials studied were polycrystalline compounds Er2-xTbxFe14B (x = 0.1, 0.2, 0.3, 0.4) which crystallize in a tetragonal lattice and display a variety of spin arrangements. The compounds have been measured with 57Fe Mössbauer spectroscopy over the temperature range 80–320 K in order to investigate the spin reorientation processes. Each compound was studied in a wide temperature range, with precise Mössbauer scanning in the vicinity of the transition. The set of spectra obtained for a given compound was analyzed using simultaneous fi tting procedure to investigate the infl uence of the transition on the shape of the spectra. The fi tting program was specifi ed to analyze the transition according to the ‘two state model’: spins fl ip abruptly from initial angle to fi nal arrangement (90° angle). Obtained results suggest that spin reorientation process cannot be described using only the mentioned above model. Additional computer simulations based on the Yamada–Kato model were conducted to determine temperature range and the type of spin alignments in the vicinity of the transition. These theoretical results supported by spectra analysis suggest the existence of intermediate (canted) spin arrangements in the studied compounds. The spin arrangement diagram was constructed.

2

Crystal electric field parameters determination for R2Fe14B compounds based on Yamada - Kato model

Bogacz B. F., Pędziwiatr A. T.

Nukleonika

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2013

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Vol. 58, No. 1

31-33

EN

Semi-empirical model developed by Yamada-Kato enables calculation of magnetic spin directions for R2Fe14B compounds, based on minimization of free energy, and - in further steps - determination of spin reorientation temperatures for transitions from basal plane to axial easy magnetization direction. In our study, this model has been successfully used to determine crystal field and exchange field parameters for Er2-xCexFe14B compounds based on spin reorientation temperatures obtained experimentally from Mössbauer measurements.

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Spin arrangement diagrams for Er2-xRxFe14B (R = Y, Ce) obtained with Mössbauer spectroscopy and phenomenological model

Pędziwiatr A., Bogacz B., Gargula R.

Nukleonika

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2003

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Vol. 48,suppl.1

59-63

EN

Two isostructural series of polycrystalline compounds: Er2-xYxFe14B and Er2-xCexFe14B have been studied by 57Fe Mössbauer spectroscopy in the temperature range 80-370 K. The spin reorientation phenomenon (a transition from basal plane to axial easy magnetisation direction) has been studied extensively by a narrow step temperature scanning in the vicinity of the transition. Using the procedure of subtracting the Mössbauer spectra taken for the same compound at different temperatures, it was possible to follow the influence of transition on the shape of spectra. From this procedure it was concluded that in the region of transition each subspectrum splits into two Zeeman sextets, which are characterised by different hyperfine magnetic fields and quadrupole splittings. The consistent way of describing the Mössbauer spectra was proposed. The spin reorientation temperatures have been established for all compositions and compared with the values obtained from theoretical calculations of spin orientation angle based on phenomenological model. The spin arrangement diagrams have been constructed.