Distributions of the hyperfine interaction parameters in (Er1−xSmx)2Fe14B as seen by Mössbauer spectroscopy (original) (raw)
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Mössbauer effect study of (Er1-xPrx)2Fe14B system
Journal of Magnetism and Magnetic Materials, 1991
Spin reorientation in (Er1-xPrx)2Fe14B system, caused by the competition between the magnetic anisotropies of the erbium and iron sublattices, was observed by 57Fe Mössbauer spectroscopy for Er-rich compositions at low temperature. It was found that substitution of Pr for Er has only minute influence on the hyperfine interaction parameters at iron crystal sites.
Mössbauer effect evidence of spin reorientation in (Er 1 − x Ce x ) 2Fe 14B intermetallic compounds
Journal of Alloys and Compounds, 1996
in (Er,_,Ce,),Fe,,B system, originating from competition between the magnetic anisotropies of the erbium and iron sublattices, was observed by the 57Fe MGssbauer spectroscopy below room temperature. The spin transition temperature is lowered by non-magnetic dilution within the rare earth crystal sublattice, caused by substitution of cerium for erbium. There is evidence that the process proceeds not at a discrete temperature but in a wide temperature range. The discrete values of the "Fe hypetie interaction parameters, derived from MGssbauer absorption spectra, are consistent with localized interactions of iron atoms with their nearest neighbours. It was found that substitution of cerium for erbium slightly reduces hyperflne magnetic fields at iron sites and it only has a minute influence on the values of the isomer shifts and quadrupole interactions. Keywords: Spin reorientation; Ternary rare earth compounds; R-Fe-B compounds; MGssbauer effect 09258388/96/$15.00 0 1996 Elsevier Science S.A. All rights reserved SSDlO925-8388(95)01945-6
A Mössbauer study of R6Fe13X (R=Pr, Nd; X=In, Sn, Tl, Pb, Cu, Ag, Au)
Hyperfine Interactions, 1994
Compounds with the composition R6Fet3X (R = Pr, Nd; X = In, Sn, TI, Pb, Cu, Ag, Au) were studied by 57Fe MOssbauer spectroscopy. Attention was focused on the influence of the easy axis of the magnetization on the shape of the hyperfine patterns. The spectra are composed of at least four subpatterns, originating from the different Fe lattice sites. Contrary to the magnetization, a significant dependence of the hyperfine parameters on the specific elements R and X could not be detected. Predominantly, the easy axis of the magnetization was found to lie within the basal plane; only for R = Nd and X = In, Sn, T1, Pb is an easy c-axis present. Since the low temperature magnetization data obtained for the different compounds show a wide spread, while the 57Fe hyperfine fields remain almost constant over the whole series, some kind of antiferromagnetic ordering within the Fe sublattice is anticipated.
Mössbauer effect evidence of spin reorientation in (Er1 − Ce )2Fe14B intermetallic compounds
Journal of Alloys and Compounds, 1996
Spin reorientation in (Er,_,Ce,),Fe,,B system, originating from competition between the magnetic anisotropies of the erbium and iron sublattices, was observed by the 57Fe MGssbauer spectroscopy below room temperature. The spin transition temperature is lowered by non-magnetic dilution within the rare earth crystal sublattice, caused by substitution of cerium for erbium. There is evidence that the process proceeds not at a discrete temperature but in a wide temperature range. The discrete values of the "Fe hypetie interaction parameters, derived from MGssbauer absorption spectra, are consistent with localized interactions of iron atoms with their nearest neighbours. It was found that substitution of cerium for erbium slightly reduces hyperflne magnetic fields at iron sites and it only has a minute influence on the values of the isomer shifts and quadrupole interactions.
Magnetic and Mössbauer spectral studies of R3Fe29−Mo compounds (R = Y, Nd, Sm, Gd, Tb, and Dy)
Journal of Alloys and Compounds, 2005
The investigation of the structure, magnetic and Mössbauer properties for the series of R 3 (Fe,Mo) 29 compounds has been performed, where R = Y, Nd, Sm, Gd, Tb, and Dy. The crystallographic structure of the ternary phase compounds has been investigated by Rietveld refinement of the X-ray diffraction patterns obtained at room temperature. The quality of the single-phase compounds was also checked by thermomagnetic measurements, from room temperature to above the Curie temperatures. From the magnetic isotherms for the free powder samples, measured at 4.2 K, the saturation magnetizations and the iron average magnetic moments have been derived. 57 Fe Mössbauer spectra of the R 3 (Fe,Mo) 29 compounds have been measured at 15 K. The analysis of spectra, in a model which takes into account both the Fe atom nearest neighbor numbers and the Fe Fe nearest neighbor bond lengths, indicates that the transferred contribution to the hyperfine field at the iron sites, due to rare earth moments, can be correlated with the rare earth effective spin.
Nukleonika
Two isostructural series of polycrystalline compounds: Er 2−x Y x Fe 14 B and Er 2−x Ce x Fe 14 B have been studied by 57 Fe 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.
Magnetic and Mössbauer spectral studies of R 3Fe 29− x Mo x compounds (R = Y, Nd, Sm, Gd, Tb, and Dy
Solid State Ionics, 2005
The investigation of the structure, magnetic and Mössbauer properties for the series of R 3 (Fe,Mo) 29 compounds has been performed, where R = Y, Nd, Sm, Gd, Tb, and Dy. The crystallographic structure of the ternary phase compounds has been investigated by Rietveld refinement of the X-ray diffraction patterns obtained at room temperature. The quality of the single-phase compounds was also checked by thermomagnetic measurements, from room temperature to above the Curie temperatures. From the magnetic isotherms for the free powder samples, measured at 4.2 K, the saturation magnetizations and the iron average magnetic moments have been derived. 57 Fe Mössbauer spectra of the R 3 (Fe,Mo) 29 compounds have been measured at 15 K. The analysis of spectra, in a model which takes into account both the Fe atom nearest neighbor numbers and the Fe Fe nearest neighbor bond lengths, indicates that the transferred contribution to the hyperfine field at the iron sites, due to rare earth moments, can be correlated with the rare earth effective spin.
Spin reorientation phenomena in Er2-xRxFe14B (R = Gd, Th) - Mössbauer and calorymetric study
Nukleonika
The Er 2−x Gd x Fe 14 B (x = 0.5, 1.0, 1.5) and Er 2−x Th x Fe 14 B (x = 0.0, 0.5, 1.0, 1.5, 2.0) polycrystalline compounds have been investigated with 57 Fe Mössbauer spectroscopy and differential scanning calorimetry (DSC). A comparison of results related to spin reorientation phenomena obtained for Gd-and Th-substituted compounds is presented in this paper. Spin reorientation phenomena (changes from planar to axial spin arrangements) have been studied extensively by a narrow step temperature scanning in the neighbourhood of the spin reorientation temperature, T SR. From the analysis of Mössbauer spectra, it was deduced that in the region of transition each subspectrum was split into two Zeeman sextets, which were characterised by different hyperfine magnetic fields and quadrupole splittings. A consistent way of fitting the spectra in the wide range of temperatures was proposed. The composition and temperature dependencies of hyperfine interaction parameters and subspectra contributions were derived from fits and the transition temperatures were determined for all the compounds studied. DSC studies proved that the spin reorientations were accompanied by thermal effects for all compositions of the Gd-and for x = 0.5 of the Th-series. Transformation enthalpy and T SR were determined from these studies and the two-stage character of transition was confirmed. Magnetic spin arrangement diagrams for R = Th and Gd series were constructed and compared using combined data obtained with both methods.