8 Mössbauer Spectroscopy in External Magnetic Fields
427
Fig. 8.46 Comparison of the
x dependence of C mag per Fe
atom from magnetization
measurements (full triangle
down, left-hand scale) with
that of ¯
C M B
core from Mössbauer
measurements (full squares).
Inset: Dependence of local
susceptibility χ M B
loc on
number of nearest Fe
neighbours in Y(Fe x Al 1−x ) 2
at 300 K; x = 0.25 (full
square), 0.40 (full circle),
0.65 (full triangle up) and
0.75 (full triangle down)
[150]. © IOP Publishing.
Reproduced with permission.
All rights reserved
Fig. 8.47 Spectra of
Y(Fe 0.75 Al 25 ) 2 in different
fields at 70 K (left) and 200 K
(right). Fits according to
described model. Reprinted
from [154]
an example of a fit in the fast relaxation limit with 9 subspectra according to a hyperfine field distribution. The structure in the calculated spectrum is not visible in the
measured one, and could be avoided by increasing the number of subspectra. The fit
is reasonable, but there is no meaningful interpretation, because the subspectra with
the largest magnetic hyperfine splitting have hyperfine fields larger than the applied
field. Because all spectra are fully polarized, it has to be concluded, that there are
contributions to the hyperfine field which are parallel to the applied field B a . This
would imply magnetic moments which are antiparallel to B a , a scenario not very
427
Fig. 8.46 Comparison of the
x dependence of C mag per Fe
atom from magnetization
measurements (full triangle
down, left-hand scale) with
that of ¯
C M B
core from Mössbauer
measurements (full squares).
Inset: Dependence of local
susceptibility χ M B
loc on
number of nearest Fe
neighbours in Y(Fe x Al 1−x ) 2
at 300 K; x = 0.25 (full
square), 0.40 (full circle),
0.65 (full triangle up) and
0.75 (full triangle down)
[150]. © IOP Publishing.
Reproduced with permission.
All rights reserved
Fig. 8.47 Spectra of
Y(Fe 0.75 Al 25 ) 2 in different
fields at 70 K (left) and 200 K
(right). Fits according to
described model. Reprinted
from [154]
an example of a fit in the fast relaxation limit with 9 subspectra according to a hyperfine field distribution. The structure in the calculated spectrum is not visible in the
measured one, and could be avoided by increasing the number of subspectra. The fit
is reasonable, but there is no meaningful interpretation, because the subspectra with
the largest magnetic hyperfine splitting have hyperfine fields larger than the applied
field. Because all spectra are fully polarized, it has to be concluded, that there are
contributions to the hyperfine field which are parallel to the applied field B a . This
would imply magnetic moments which are antiparallel to B a , a scenario not very