Mössbauer Study of Hexagonal FeGe

Abstract

Mössbauer spectroscopic studies of the hexagonal antiferromagnet FeGe have been undertaken in the temperature range 10-430 K. The temperature variation of the magnetic hyperfine field for iron deviates from Brillouin function behaviour. From the values of B hf close to the ordering temperature the critical exponent β=0.328 and the Neél temperature T N=398 K were obtained. The close similarity between isostructural binary compounds in the iron-germanium and the iron-tin systems as regards magnetic properties is stressed.

Dependence of the Fe anisotropy on the Dy concentration in the DyxFe6Sn6 (0.3<x<1) compounds

“…As previously explained in detail [11,18,19] when the µ Fe direction is parallel to the c-axis a single sextet is observed, but when µ Fe deviates from this direction three different sextets are observed for the crystallographic equivalent Fe atoms as reported for FeSn [17,18], YbFe 6 Ge 6 at 4 K [19], Yb 0.6 Fe 6 Sn 6 [9], U x Fe 6 Sn 6 (0 < x < 0.6) [11].…”

“…3) are clearly different from those of DyFe 6 Sn 6 or of Dy 0.5 Fe 6 Sn 6 at 10 K. They have features similar to those reported for FeSn [17,18], YbFe 6 Ge 6 at 4 K [19], Yb 0.6 Fe 6 Sn 6 [9], U x Fe 6 Sn 6 (0 < x < 0.6) [11]. On the other hand, labeling the six lines Table 1 Estimated parameters from the Mössbauer spectra of Dy x Fe 6 Sn 6 (0.3 ≤ x ≤ 1) taken at different temperatures T observed in the 295 K spectrum of Dy 0.5 Fe 6 Sn 6 from 1 to 6 from negative to positive velocities, peaks 1 and 5 appear to be narrower than peaks 2 and 6, respectively, as also found for A x Fe 6 Sn 6 (A = Sc, Zr, Tm, Yb, Lu) [9,12].…”

“…Therefore, the determination of the EFG main axes is not straightforward. As calculated for the binary CoSn-type FeX parent compounds [17,18] there are three sets of principal EFG axes for the three iron atoms of each (0 0 1) Fe layer in a unit cell. The similarity of the Mössbauer spectra of Yb 0.6 Fe 6 Sn 6 and U x Fe 6 Sn 6 with those of AFe 6 Ge 6 , where µ Fe were found to lie in the ab-plane by neutron diffraction, led to the conclusion that in Yb 0.6 Fe 6 Sn 6 and U x Fe 6 Sn 6 V zz also lies in the ab-plane [9,11].…”

Neutron diffraction determination of the magnetic structure of DyFe6Ge6

“…The 57 Fe B hf -value of 14.7(1) T at 295 K [3] can be translated into an Fe atomic magnetic moment if one knows the conversion factor. As discussed in our previous paper [5], Häggström et al [17] compiled field-moment conversion factors for a number of Fe-Ge binary compounds, taken from the literature, and found a conversion factor of 11.2(25) T/µ B . Adopting this value, our 57 Fe Mössbauer B hf -value for DyFe 6 Ge 6 corresponds to an Fe moment of 1.3(3) µ B at 295 K, in agreement with the neutron diffraction result.…”

A study on the magnetic behaviour of polymorphic YbFe6Ge6

“…The magnetism of the FeGe basis has been the subject of extensive investigation over the past four decades. This work encompasses 57 Fe Mössbauer spectroscopy [8][9][10], magnetic measurements [11][12][13], neutron diffraction [14][15][16] and theoretical studies [17,18]. The Fe sublattice orders antiferromagnetically below 410 K with the Fe moments aligned along the hexagonal C-axis.…”