Mössbauer studies of REFe2Si2 (RE=Gd-Lu) compounds

doi:10.1016/0304-8853(83)90091-4

Journal of Magnetism and Magnetic Materials

Volume 39, Issue 3, 1 December 1983, Pages 309-316

https://doi.org/10.1016/0304-8853(83)90091-4 Get rights and content

Abstract

Magnetic transition temperatures and results of ⁵⁷Fe, ¹⁵⁵Gd, ¹⁶⁶Er and ¹⁷⁰Yb Mössbauer effect studies of REFe₂Si₂ compounds are presented. The ⁵⁷Fe Mössbauer effect establishes that Fe never has a magnetic moment in these materials. Line broadenings seen in low temperature ⁵⁷Fe spectra are attributed to polarization of conduction electrons at the Fe site due to rare-earth magnetic ordering (or slow relaxation). The lattice-generated electric field gradient at the RE site, deduced from the ¹⁵⁵Gd quadrupole interaction in GdFe₂Si₂, is used to produce a crystalline electric field model for the magnetic behavior of the other members of this isostructural series. This model is instrumental in understanding the ¹⁶⁶Er Mössbauer effect in ErFe₂Si₂ and ¹⁷⁰Yb Mössbauer effect in YbFe₂Si₂.

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The present neutron diffraction data revealed the absence of any magnetic moment on the Fe atoms sites, similarly to the results obtained for other isostructural RFe2X2 (X=Si, Ge) compounds [2,3]. This finding is also in good agreement with the Mössbauer spectroscopy data, which indicated nonmagnetic nature of the Fe atoms [11]. The valence band XPS spectra recorded for the isostructural compound HoFe2Ge2 revealed that the 3d states due to Fe atoms form a broad maximum below the Fermi level [16].
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This slowing down is far from what would be observed if magnetic ordering or spin-glass freezing of μFe occurred. It is rather similar to the effect attributed to polarization of the conduction electrons at the iron sites in RFe2Si2 compounds due to R, the rare-earth, magnetic ordering [20]. In contrast to RFe2Si2, however, the enhanced effective magnetic moment deduced for the present U3Fe4+xAl12−x, suggests a non-zero μFe.
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^☆: Work supported by the US Department of Energy.

^†: Present address: TRIUMF, University of British Columbia, Vancouver, Canada.

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Topical reviewMössbauer studies of REFe2Si2 (RE=Gd-Lu) compounds☆

Abstract

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J. Less Common Metals

Solid State Common.

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Solid State Commun.

J. Less Common Metals

Phys. Rev. B

Phys. Rev. Lett.

Phys. Rev. Lett.

Phys. Lett.

J. Appl. Phys.

Solid State Commun.

Phys. Rev. Lett.

Solid State Commun.

Phys. Rev. B

Monatsh. Chem.

J. Appl. Phys.

Solid State Commun.

Topical review
Mössbauer studies of REFe₂Si₂ (RE=Gd-Lu) compounds☆