Mössbauer spectroscopy of Fe-based nanomaterials

Abstract

X-ray diffraction, magnetic measurements and Mössbauer spectroscopy were used to study magnetic properties and hyperfine interaction parameters of nanocrystalline (< 10 nm) and bulk bcc Fe, Fe90Ge10, and Fe77Al23 alloys. It has been established that nanocrystalline state does not influence the formation of specific saturation magnetization, Curie temperature, isomer shift and hyperfine magnetic field. No additional sextets in Mössbauer spectra as well as special features in temperature dependences of a.c. magnetic susceptibility have been found. A slight increase (∼ 20%) of the width of the nanocrystalline Fe Mössbauer spectral lines has been observed.PACS : 75.50.Bb

The structure and magnetic properties of the non-equilibrium Fe100−xGex (x=5-40 at%) system produced by mechanical alloying

“…5b. The change of the behaviour of them Fe value in the Fe-Ge alloys occurs in the vicinity of 15 at%, which exceeds the values for the Fe-Si alloys (E8 at%) [1,3] and equilibrium crystalline solid solutions of Fe-Ge (E12 at%) [23] and they are lower than those of the Fe-Sn alloys (E20 at%) [6,7]. In general, them Fe values obtained over the whole range of existence of the disordered BCC structure in the Fe-Ge system agree with those obtained in Refs.…”

“…9a it is seen that there is a good agreement of H K values obtained in this work for disordered alloys with the data published for intermetallic compounds with a known local environment of Fe atoms. According to this dependence H K turns to zero with the critical number of metalloid atoms K C =10, while for Fe-Si K C =7 [1][2][3] and for Fe-Sn K C =11 [7,8]. Earlier in Ref.…”

“…The studies of the BCC disordered nanocrystalline Fe alloys with Si N Sn [1][2][3][4][5][6][7][8] revealed both general regularities and differences in the formation of their magnetic properties. It was shown that despite the isoelectron structure of the external shell of Si (3s 2 p 2 ) and Sn (5s 2 p 2 ) atoms, one can observe some differences in the behaviour of the concentration dependences of the hyperfine magnetic field (HFMF)H at the 57 Fe nucleus and magnetic moment per iron atomm Fe : To study the effect of the element type on the formation of magnetic properties, further comparative investigation of disordered nanocrystalline Fe-Ge alloys was of interest since the Ge atom has an isoelectron structure of the external shell (4s 2 p 2 ) with the Si and Sn atoms and intermediate with value of the covalent radius 0.122 nm (0.11 and 0.141 nm for Si and Sn, respectively).…”

Iron-containing nanomaterials: synthesis, properties, and environmental applications

“…58 X-Ray diffraction, magnetic measurements and Mo ¨ssbauer spectroscopy were used to study magnetic properties and hyperfine interaction parameters of nanocrystalline (,10 nm) and bulk bcc Fe, Fe 90 Ge 10 and Fe 77 Al 23 alloys. 59 It was established that the nanocrystalline state does not influence the formation of specific saturation magnetization, Curie temperature, isomer shift and hyperfine magnetic field. A slight increase (y20%) of the width of the nanocrystalline iron Mo ¨ssbauer spectral lines was observed.…”