Abstract:
We have investigated the contribution of Ce
4
f
states to the electronic structure of the intermetallic ferromagnet
CePdIn
2
by means of x-ray absorption spectroscopy and resonant and nonresonant photoemission spectroscopy. The line shape of the Ce
M
5
,
4
absorption edge reveals the localized nature of the
4
f
states, and is consistent with a predominantly 3+ ionic state for Ce ions. Fitting of the Ce
3
d
core level gives a Ce
4
f
occupation number at room temperature of 0.92, which is in good agreement with the Ce effective magnetic moment of
2.20
μ
B
(corresponding to
∼
87
%
of the free-electron moment) as calculated from the inverse magnetic susceptibility. Moreover, the hybridization strength between
4
f
and conduction electrons is found to be
∼
180
meV, revealing that
CePdIn
2
is a strongly hybridized system. This is consistent with the results from the analysis of the resonant valence band photoemission measurements at both the
N
5
,
4
and the
M
5
edges, showing that the Ce
4
f
states are composed of the features predicted by the single-impurity Anderson model, i.e., a broad
4
f
0
peak centered at 1.9 eV and two
4
f
1
spin-orbit states much closer to the Fermi level. The same spectra also show that the Ce
4
f
resonant spectral weight extends over a wide binding energy range, overlapping with that presumably occupied by the Pd
4
d
ligand states. This energy overlap is interpreted as a signature of the strong hybridization governing the system, which could possibly favor the emergence of long-range ferromagnetism through the indirect exchange between localized
4
f
states mediated by highly dispersive
d
electrons.
DOI: https://journals.aps.org/prb/abstract/10.1103/PhysRevB.92.235137