Evidence of collinear ferrimagnetism in (Fe, Tb)B metallic glasses from polarized beam neutron scattering

Abstract

The atomic-scale magnetic structures of two terbium-substituted (Fe0.83−xTbx)B0.17 metallic glasses have been determined by polarized beam neutron scattering measurements using the IN20 spectrometer at the Institut Laue-Langevin, Grenoble. The four spin-dependent, neutron scattering cross-sections were measured in absolute units for the two glasses. The spin-flip cross-sections and were found to be small; they were independent of the scattering vector Q, independent of the temperature and were also of the same magnitude as the nuclear incoherent cross-section, within experimental errors. These observations indicate that the magnetic structure in these glasses must be collinear. The non-spin-flip cross-sections were found to have a hitherto unobserved shift of the first peak between the and channels. A (collinear) ferrimagnetic state which is consistent with the spin-flip cross-sections is therefore proposed for these glasses. The magnetic moments on the terbium atoms are aligned antiparallel to those on the iron atoms, and the values of both moments reduce to zero by x = 0.50 terbium, in agreement with magnetization data. A calculation of the non-spin-flip cross-sections based on this model correctly predicts the shift of the first peaks. This behaviour arises because of the ferrimagnetic correlations between the magnetic moments and the very strong magnetic scattering from the terbium atoms.

Sperimagnetism in Fe78Er5B17and Fe64Er19B17metallic glasses: II. Collinear components and ferrimagnetic compensation

“…They are similar to some of the first spin-dependent cross-sections which were measured for metallic glasses, such as Co 81 P 19 [12], Co 81.5 B 18.5 [13] and Fe 83 B 17 [14] and also to the non spin-flip cross-sections of some of the (Fe,Tb) 83 B 17 glasses [3]. The first peak in The derivation of the spin-dependent total structure factors is illustrated in Figure 2 Table 1 of .…”

“…Our studies of the collinear and non-collinear magnetic structures in metallic glasses [1] were described in Part I [2], where it was explained that the non spin-flip neutron scattering crosssections of (Fe,Tb) 83 B 17 glasses had been simulated using a combination of known and derived partial structure factors [3]. The related (Fe,Er) 83 B 17 glass have been shown to be a non-collinear ferrimagnets by a variety of different measurements [4,5,6,7,8], but our preliminary neutron scattering measurements on a Fe 64 Er 19 B 17 glass at 1.5K, 60K and 180K proved to be difficult to interpret [9].…”

“…Comparison with the cross-sections of the (Fe,Tb) 83 B 17 collinear ferrimagnets [3] suggests that at high temperatures the iron sublattice points along the field direction and the erbium sublattice is antiparallel to it ( Fe : Er ) and the inverted case ( Fe : Er ).…”

Sperimagnetism in Fe78Er5B17and Fe64Er19B17metallic glasses: I. Moment values and non-collinear components

“…The Table shows that the values of Comparing the present moment values with those obtained elsewhere, the new value of || Er µ = 6.58 B means that the total moment on the erbium atoms must be in the region of Er µ ≈ 8.8 B , if the random cone angle is Er ≈ 60º as suggested in [9]. Our previous experience with the (Fe,Tb) 83 B 17 glasses [4,14] led us to doubt that the erbium moment in the (Fe,Er) 83 B 17 glasses changed slowly on alloying [6,7], but this indeed appears to be the case. Information from previous magnetisation and Mössbauer spectroscopy measurements [5,6,9] on similar samples has already been incorporated into the present analysis, so this has led a measure of agreement.…”

Spin reorientation and magnetoelastic coupling in Tb6Fe1−Co Bi2 (x= 0, 0.125, 0.25, and 0.375) alloy system

“…5(b). This ferromagnetism between terbium atoms and ferrimagnetism between iron and terbium is not uncommon [18][19][20][21].…”