Mossbauer Sextet Research Articles

Сanted Magnetic Interlayer Ordering in a [Fe(3.0 nm)/Cr(1.2 nm)]10 Structure Revealed by Synchrotron Mössbauer Reflectometry with Polarization Analysis

Mossbauer reflectivity spectra measured for the [Fe(3.0 nm)/Cr(1.2 nm)]10 structure in the half-order Bragg peak, which corresponds to the doubling of the period, have revealed the formation of a canted antiferromagnetic structure under the action of an external magnetic field of $${{B}^{{{\text{ext}}}}} = 0.06$$ Т applied perpendicular to the scattering plane. This result certainly follows from the appearance of the second and fifth lines in the Mossbauer sextet, which should be suppressed for any symmetric orientation of the magnetic hyperfine field in two 57Fe layers in one magnetic period. The experiment involves a polarization analysis of the reflected beam and shows that this new approach simplifies the form of angular dependences and reflectivity spectra, since it eliminates the interfering contribution of nonresonant scattering, and improves the reliability of the data interpretation.

Mössbauer Study and Curie Temperature Configuration on Sintering Nano-Ni-Zn Ferrite Powder

Variations of Curie temperature and strength of magnetic phases with sintering temperature and Ni concentration is investigated in the present work. The AC susceptibility studies show a decrease in Curie temperature (TC) with an increase in Ni concentration in the samples. Comparison of Curie temperatures with the reported results reveals that samples in the present work show higher TC enabling high thermal stability. The Mossbauer spectra of nano- and sintered Ni-Zn ferrite samples were recorded at room temperature to monitor the local environment around Fe cations through Mossbauer hyperfine parameters as a function of composition and sintering temperatures. The increase in sharpness of the Mossbauer sextet with an increase in Ni concentration and sintering temperature corroborate improvement in homogeneity and ferrimagnetic ordering. The results of hyperfine parameters offer the possibility of having close view on configuring Curie temperature through monitoring hyperfine field by altering sintering temperature and/or Ni concentration. As the temperature dependence of magnetic and magnetoelastic properties is strongly influenced by the Curie temperature, the successful possible configuration of Curie temperature in the present work can be further investigated for desired sensor applications.

57 Fe Mössbauer study of spin reorientation transition in polycrystalline NdFeO 3

Abstract The present work reports the preparation of polycrystalline NdFeO 3 using sol-gel method and characterization using X-ray diffraction (XRD), Raman spectroscopy, bulk magnetization, 57 Fe Mossbauer spectroscopy and ferroelectric measurements. XRD and Raman spectroscopy measurements confirm the phase purity of the prepared sample. The temperature dependent magnetization measurement shows the signatures of spin re-orientation transition ( T SRT ) between 66 and 158 K and magnetic field induced transition at about 2.5 T and 5 K. It is observed from the low temperature (25–300 K) 57 Fe Mossbauer measurements that the temperature variation of hyperfine parameters shows the signatures of T SRT . The observed area ratio of second and third line intensity (A 23 ) in Mossbauer sextet, across T SRT , show deviations from the value characteristic of random spin orientation in polycrystalline sample. In addition, the quadrupole shift changes sign across T SRT indicating the spin-reorientation of Fe 3+ ions. The room temperature leakage current density ( J - E ) measurements indicate that Ohmic contribution and space charge limited conduction are the dominating mechanisms at low and high applied electric fields, respectively, similar to that of other RFeO 3 (R – rare earth) based compounds. Lossy ferroelectric loops were observed at room temperature.

Structural Characterization of Highly Corrosion-resistant Steel

Structural features of novel corrosion-resistant LC 200N steel were investigated. Mossbauer spectrometry was chosen as a principal method of investigation. Surface as well as bulk properties were studied using Conversion Electron Mossbauer Spectrometry and transmission technique, respectively. Complex behaviour of magnetic and non-magnetic phases was identified in the samples by these two techniques. Chemical composition was checked by neutron activation analysis and X-ray fluorescence technique. Structural arrangement was studied by scanning electron microscopy with energy dispersive spectrometry and transmission electron microscopy. They unveiled regions with fairly varied Cr concentrations. Basing on a simple model of two different Cr concentrations, the relative areas of the Mossbauer sextets were modelled by a linear combination of two binomial distributions.

Modification of magnetic anisotropy in ferromagnetic metallic glasses using high energy ion beam irradiation

The modification in the magnetic anisotropy introduced by swift heavy ion irradiation has been investigated. Ferromagnetic metallic glasses Fe 78B 13Si 9 and Fe 40Ni 38Mo 4B 18 have been irradiated with 100 MeV 127I ions at different doses from 5×10 12 to 7.5×10 13 ions/cm 2. Magnetic anisotropy has been studied by measuring the relative intensity ratio D 23 of Mossbauer sextet. As received samples display orientation of the magnetic moments nearly parallel to the surface of the ribbon, which upon irradiation to a dose of 5×10 12 ions/cm 2 rotates to a nearly random orientation. At the dose of 7.5×10 13 ions/cm 2, the magnetic moments display completely random orientation.

Local field fluctuations in the substituted aluminum iron garnets, Y 3Fe 5− xAl xO 12

The saturation magnetizations and the Mossbauer spectrums of substituted aluminum iron garnets, Y 3Fe 5− x Al x O 12, at room temperature are reported. It is seen that the saturation magnetizations initially decreases in a linear manner as Al 3+ replaces the Fe 3+ and then deviates from the linearity as more Fe is replaced. The hyperfine fields for the ` a' site Fe ions are seen to decrease as the Al content increases, while the hyperfine fields for the ` d' site Fe ions shows no changes at the initial doping levels. The half width of the lines in the Mossbauer sextets for the ` a' site ions is seen to increase with the increase in the Al content. This broadening is interpreted as being due to the local fluctuations arising at these sites from the increasing disorder occurring in the ` d' sub-lattice as more Al is added.

Mössbauer six-line spectra position analysis for Fe57 in metallic iron

The formulae for evaluating the parameters of magnetically split Mossbauer six-line spectra with quadrupole splitting from measured line positions are derived. Some special cases are considered and the suitability of the centre of gravity rule for the shift determination as well as the case of the internal magnetic field measurement from the distance of the outermost lines of the Mossbauer sextet are discussed. From the measured spectra of metallic iron the ratio of magnitudes of the nuclear magnetic moments for Fe57 ¦μ1/μ0¦= 1·701±0·008 is derived by means of the proposed method. Further, the internal magnetic field intensity at the Fe57 nucleus in metallic ironH i =(329·4±1·2) kOe and other quantities are determined.