Magnetic anisotropy in Fe phthalocyanine film deposited on Si(110) substrate: standing configuration
In this contribution we report on the structural and magnetic properties of an Fe phthalocyanine (FePc) thin film deposited on a silicon substrate. The planar FePc molecules order spontaneously in a standing configuration, i.e., with the molecular plane perpendicular to the substrate. The x-ray line...
Gespeichert in:
| Veröffentlicht in: | Физика низких температур |
|---|---|
| Datum: | 2017 |
| Hauptverfasser: | , , , , , |
| Format: | Artikel |
| Sprache: | English |
| Veröffentlicht: |
Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
2017
|
| Schlagworte: | |
| Online Zugang: | https://nasplib.isofts.kiev.ua/handle/123456789/175124 |
| Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Zitieren: | Magnetic anisotropy in Fe phthalocyanine film deposited on Si(110) substrate: standing configuration / J. Bartolomé, F. Bartolomé, L.M. García, T. Gredig, I.K. Schuller, J.C. Cezar // Физика низких температур. — 2017. — Т. 43, № 8. — С. 1189-1193. — Бібліогр.: 22 назв. — англ. |
Institution
Digital Library of Periodicals of National Academy of Sciences of Ukraine| id |
nasplib_isofts_kiev_ua-123456789-175124 |
|---|---|
| record_format |
dspace |
| spelling |
Bartolomé, J. Bartolomé, F. García, L.M. Gredig, T. Schuller, I.K. Cezar, J.C. 2021-01-30T18:02:29Z 2021-01-30T18:02:29Z 2017 Magnetic anisotropy in Fe phthalocyanine film deposited on Si(110) substrate: standing configuration / J. Bartolomé, F. Bartolomé, L.M. García, T. Gredig, I.K. Schuller, J.C. Cezar // Физика низких температур. — 2017. — Т. 43, № 8. — С. 1189-1193. — Бібліогр.: 22 назв. — англ. 0132-6414 PACS: 75.30.Gw, 75.70.–i, 75.75.–c https://nasplib.isofts.kiev.ua/handle/123456789/175124 In this contribution we report on the structural and magnetic properties of an Fe phthalocyanine (FePc) thin film deposited on a silicon substrate. The planar FePc molecules order spontaneously in a standing configuration, i.e., with the molecular plane perpendicular to the substrate. The x-ray linear polarized absorption and x-ray magnetic circular dichroism experiments at the Fe-L2,3 edges at T = 6 K were performed, concluding that at this temperature the film displays magnetic anisotropy with the main easy axis perpendicular to the substrate. This result is explained in terms of the FePc single molecule anisotropy which has its larger moment in the molecule plane. Thus, the standing configuration in polycrystalline thin films favors statistically that, at the macroscopic array level, the magnetic easy anisotropy axis is normal to the substrate. The financial support of the Spanish MINECO MAT2014-53921-R and Aragonese DGA-IMANA E34, both cofunded by Fondo Social Europeo and European Union FEDER funds is acknowledged. T.G. acknowledges support from the National Science Foundation (NSF) DMR-0847552 and the W.M. Keck Foundation. The XMCD experiments were performed at the ID08 (now ID32) beamline of the ESRF, experiment HE2486. This is a highly collaborative research. The experiments were conceived jointly, the data was extensively debated and the paper was written by multiple iteration between all the coauthors. Samples were fabricated, characterized and prepared at UCSD (T.G. and I.K.S.). The research at UCSD was supported by the Office of Basic Energy Science, U.S. Department of Energy, BES-DMS funded by the Department of Energy's Office of Basic Energy Science, DMR under Grant No. DE FG02 87ER-45332. en Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України Физика низких температур Low dimensionality and inhomogeneity effects in quantum matter Magnetic anisotropy in Fe phthalocyanine film deposited on Si(110) substrate: standing configuration Article published earlier |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| title |
Magnetic anisotropy in Fe phthalocyanine film deposited on Si(110) substrate: standing configuration |
| spellingShingle |
Magnetic anisotropy in Fe phthalocyanine film deposited on Si(110) substrate: standing configuration Bartolomé, J. Bartolomé, F. García, L.M. Gredig, T. Schuller, I.K. Cezar, J.C. Low dimensionality and inhomogeneity effects in quantum matter |
| title_short |
Magnetic anisotropy in Fe phthalocyanine film deposited on Si(110) substrate: standing configuration |
| title_full |
Magnetic anisotropy in Fe phthalocyanine film deposited on Si(110) substrate: standing configuration |
| title_fullStr |
Magnetic anisotropy in Fe phthalocyanine film deposited on Si(110) substrate: standing configuration |
| title_full_unstemmed |
Magnetic anisotropy in Fe phthalocyanine film deposited on Si(110) substrate: standing configuration |
| title_sort |
magnetic anisotropy in fe phthalocyanine film deposited on si(110) substrate: standing configuration |
| author |
Bartolomé, J. Bartolomé, F. García, L.M. Gredig, T. Schuller, I.K. Cezar, J.C. |
| author_facet |
Bartolomé, J. Bartolomé, F. García, L.M. Gredig, T. Schuller, I.K. Cezar, J.C. |
| topic |
Low dimensionality and inhomogeneity effects in quantum matter |
| topic_facet |
Low dimensionality and inhomogeneity effects in quantum matter |
| publishDate |
2017 |
| language |
English |
| container_title |
Физика низких температур |
| publisher |
Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України |
| format |
Article |
| description |
In this contribution we report on the structural and magnetic properties of an Fe phthalocyanine (FePc) thin film deposited on a silicon substrate. The planar FePc molecules order spontaneously in a standing configuration, i.e., with the molecular plane perpendicular to the substrate. The x-ray linear polarized absorption and x-ray magnetic circular dichroism experiments at the Fe-L2,3 edges at T = 6 K were performed, concluding that at this temperature the film displays magnetic anisotropy with the main easy axis perpendicular to the substrate. This result is explained in terms of the FePc single molecule anisotropy which has its larger moment in the molecule plane. Thus, the standing configuration in polycrystalline thin films favors statistically that, at the macroscopic array level, the magnetic easy anisotropy axis is normal to the substrate.
|
| issn |
0132-6414 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/175124 |
| citation_txt |
Magnetic anisotropy in Fe phthalocyanine film deposited on Si(110) substrate: standing configuration / J. Bartolomé, F. Bartolomé, L.M. García, T. Gredig, I.K. Schuller, J.C. Cezar // Физика низких температур. — 2017. — Т. 43, № 8. — С. 1189-1193. — Бібліогр.: 22 назв. — англ. |
| work_keys_str_mv |
AT bartolomej magneticanisotropyinfephthalocyaninefilmdepositedonsi110substratestandingconfiguration AT bartolomef magneticanisotropyinfephthalocyaninefilmdepositedonsi110substratestandingconfiguration AT garcialm magneticanisotropyinfephthalocyaninefilmdepositedonsi110substratestandingconfiguration AT gredigt magneticanisotropyinfephthalocyaninefilmdepositedonsi110substratestandingconfiguration AT schullerik magneticanisotropyinfephthalocyaninefilmdepositedonsi110substratestandingconfiguration AT cezarjc magneticanisotropyinfephthalocyaninefilmdepositedonsi110substratestandingconfiguration |
| first_indexed |
2025-11-25T04:53:13Z |
| last_indexed |
2025-11-25T04:53:13Z |
| _version_ |
1850504441671712768 |
| fulltext |
Low Temperature Physics/Fizika Nizkikh Temperatur, 2017, v. 43, No. 8, pp. 1189–1193
Magnetic anisotropy in Fe phthalocyanine film deposited
on Si(110) substrate: standing configuration
Juan Bartolomé1, Fernando Bartolomé1, Luis Miguel García1, Thomas Gredig2,
Ivan K. Schuller3, and Julio C. Cezar4,5
1Instituto de Ciencia de Materiales de Aragón and Departamento de Física de la Materia Condensada,
CSIC-Universidad de Zaragoza, Zaragoza 50009, Spain
E-mail: Barto@unizar.es
2Department of Physics, California State University, Long Beach, CA 90840-9505, USA
3Center for Advanced Nanoscience, Department of Physics, University of California San Diego,
la Jolla, CA 92093-0319, USA
4Laboratório Nacional de Luz Síncrotron (LNLS), Campinas (SP), CEP 13083-100, Brasil
5European Synchrotron Radiation Facility (ESRF), Grenoble F380543, France
Received February 24, 2017, published online June 26, 2017
In this contribution we report on the structural and magnetic properties of an Fe phthalocyanine (FePc) thin
film deposited on a silicon substrate. The planar FePc molecules order spontaneously in a standing configura-
tion, i.e., with the molecular plane perpendicular to the substrate. The x-ray linear polarized absorption and x-ray
magnetic circular dichroism experiments at the Fe-L2,3 edges at T = 6 K were performed, concluding that at this
temperature the film displays magnetic anisotropy with the main easy axis perpendicular to the substrate. This
result is explained in terms of the FePc single molecule anisotropy which has its larger moment in the molecule
plane. Thus, the standing configuration in polycrystalline thin films favors statistically that, at the macroscopic
array level, the magnetic easy anisotropy axis is normal to the substrate.
PACS: 75.30.Gw Magnetic anisotropy;
75.70.–i Magnetic properties of thin films, surfaces, and interfaces;
75.75.–c Magnetic properties of nanostructures.
Keywords: phthalocyanine, molecular magnetism, magnetic anisotropy, XMCD.
Introduction
Molecular thin films have a broad field of applications
as coatings in optical devices and sensors. In particular,
bio-inspired oxygen-binding metalated macrocycles, such
as iron-phthalocyanines (FePc), are being investigated
due to their unique magnetic properties as a molecular
magnet [1–3]. The FePc is a planar molecule where the
Fe atom has a square planar coordination with four
pyrrolitic N atoms (see Fig. 1). When deposited on a planar
substrate the resulting configuration depends on the type of
substrate and deposition method. Organic molecular beam
epitaxy (OMBE) allows producing metallo-phthalocyanine
(MPc) (M = transition metal) films with different crystalline
orientations and order. Frequently, the planar MPc molecules
stack parallel to the substrate surface (laying configuration),
when deposited on Au [4], Ag [5–7] or Cu [8], or tilted with
the MPc plane nearly perpendicular to the substrate plane
(standing configuration), as for FePc deposited on sapphire
[4,9–11] or silicon [11,12], on polycrystalline substrates [13]
or low work function metals as Al and V [14].
In previous work [2] we found that FePc films deposit-
ed on Au, ordered in the laying configuration and had
magnetic planar anisotropy, i.e., with the magnetic easy
axis parallel to the molecule plane, thus parallel to the sub-
strate. This was quite surprising in view of the magnetic
behavior in the bulk phase [15]. The most exiciting result
was the observation by x-ray magnetic circular dichroism
(XMCD) of a large unquenched orbital moment caused by
the orbital degeneracy of the eg doublet level near the Fer-
mi energy [2].
© Juan Bartolomé, Fernando Bartolomé, Luis Miguel García, Thomas Gredig, Ivan K. Schuller, and Julio C. Cezar, 2017
Juan Bartolomé, Fernando Bartolomé, Luis Miguel García, Thomas Gredig, Ivan K. Schuller, and Julio C. Cezar
The objective of this paper is to describe the magnetic
anisotropy of a FePc thin film deposited by OBME on a
Si(110) substrate, thus in the standing configuration, and
compare results with the FePc film deposited on Au in the
laying configuration.
Experimental details
The FePc thin film was deposited on a Si(110) substrate
by OMBE. Sigma-Aldrich FePc was purified in three cy-
cles using the temperature gradient method. Outgassing the
purified material was found essential to reduce the number
of impurities and increase the crystallinity. The chamber
pressure during deposition was 1.2·10–8 Torr with the base
pressure about 5·10–9 Torr (more details in Ref. 12). De-
pending on the substrate temperature during deposition,
asymmetrical, elongated grains are formed. Between room
temperature and 200°C the grains consist of FePc mole-
cules stacked in the form of chains, with an approximately
26.5° tilting angle with respect to the chain axis b (the α
phase). The chain direction b is parallel to the substrate
plane [9,16] (see Fig. 2(a)). The measured sample had a
FePc thickness of about 80 nm.
The standing configuration of the FePc molecules was
checked by x-ray diffraction (θ–2θ diffraction patterns)
where the (200), (400) and (800) peaks of the FePc textured
sample have highest intensity (see Fig. 1 in Ref. 12). In ad-
dition, we have performed an x-ray linear polarized absorp-
tion (XLPA) experiment at the N K-edge at normal and
grazing incidence (75° from normal) (see Fig. 2(a)). As
shown in this figure, the polarization of the electric field of
the incoming photons E is denoted as horizontal (H) and
vertical (V) for parallel and perpendicular to the synchrotron
storage ring electron orbit plane, respectively. In Fig. 2(b),
the two spectra are shown: it is evident that both are very
different, with the most intense signal corresponding to the
V configuration. This is in quantitative agreement with
earlier measurements on the laying configuration, as shown
in Fig. 2, Ref. 2. These measurements therefore confirm that
in the sample discussed here, the FePc molecules are
oriented in the standing configuration.
Fig. 1. (Color online) Metallo-phthalocyanine molecule.
Fig. 2. (Color online) (a) Side view of the FePc stacking on a Si(110) substrate in the standing configuration. The incoming beam at
grazing incidence γ is shown with the E in the H and V polarization modes, at T = 6 K. The angle β between the molecule z axis and the
normal to the substrate N. Upper panel: top projection of the chains on the substrate. (b) XLPA spectra recorded at the N K-edge in
grazing angle incidence γ =75°. The two spectra correspond to the H and V polarization modes: E is either (blue, V) close to parallel to
the silicon substrate, or (red, H) forming an angle 15° with N.
1190 Low Temperature Physics/Fizika Nizkikh Temperatur, 2017, v. 43, No. 8
Magnetic anisotropy in Fe phthalocyanine film deposited on Si(110) substrate: standing configuration
The XLPA and XMCD experiments were performed at
the ID08 beamline of the European Synchrotron Radiation
Facility (ESRF) in Grenoble. The detection mode was total
electron yield (TEY). The resolution at the Fe-L2,3 energy
region is about ∆E/E = 5·10–4. The monochromatic x-ray
beam incidence angle on the sample may be varied in the
range 0 < γ < 75°. The XMCD experiment was performed
in a µ0H = 5 T applied magnetic field, parallel to the beam
direction. The polarization rate was considerably above
99%. All experiments were performed at T = 6 K.
XLPA and XMCD results
The normalized XLPA spectra in the V polarization mo-
de, measured at the Fe-L2,3 edges are shown in Fig. 3. The
absorption intensity is proportional to the number of empty
valence states in the direction of the electric field EH, which
is parallel to the substrate plane for γ = 0, and almost per-
pendicular to it for grazing incidence γ = 75°: The molecules
are in the standing configuration, with the z axis of the
molecules randomly oriented around the normal to the sub-
strate N (see Fig. 2(a)). Therefore, the vector EH, acting as
“search light”, scans a random distribution of the molecule
orientations between the z and x (or y) axes for γ = 0, and
mostly y (or x) axis for γ = 75°, the largest grazing angle
possible in the experiment.
By direct comparison to the XLPA spectra measured in
the laying configuration we can establish a direct corre-
spondence between the energy of the peaks observed in
both spectra, and as a consequence, the identification of
some of them to 2p→3d excitations [2]. The first small
peak at 706.4 eV observed at the L3 edge in the γ = 75°
spectrum can be assigned to the eg empty level with mix-
ing of the a1g level; this is a very interesting feature, spe-
cific to the FePc, which is not present in other MPc’s (M =
= Cu, Ni or Co). This reveals the existence of a split dou-
blet near the Fermi energy which causes the highly un-
quenched orbital moment [2]. The next intense peak at
707.3 eV corresponds to the excitations to the empty a1g
state (or to the Fe 2 23z r
d
−
state), which is most intense for
γ = 0, since in this incident angle the molecular z axis has
the maximal projection on the EH vector. The photon ener-
gy of the peak corresponds exactly to the values observed
for the FePc film deposited on Au in the laying configura-
tion [2]. However, the dependence of the intensity with
respect to the incident angle is just reversed, i.e., maximal
peak for standing configuration corresponds to minimal
intensity for laying configuration, and vice versa.
The x-ray absorption spectra (XAS) (not shown) and
XMCD spectra measured at the Fe-L2,3 edges in a field of
±6 T as a function of incident angle are depicted in Fig. 4.
The sum rules analysis [17,18] was applied to the XMCD
to obtain the effective spin eff
Sm and orbital Lm moments
as a function of γ. The results are shown Fig. 5.
Fig. 3. (Color online) Normalized XLPA of FePc deposited on
Si(110) at the Fe-L2,3 edges as a function of incident angle
0 < γ < 75° measured at T = 6 K.
Fig. 4. (Color online) Normalized XMCD of FePc deposited on
Si(110) at the Fe-L2,3 edges as a function of incident angle
0 < γ < 75° measured at T = 6 K.
Fig. 5. mL and eff
Sm as determined from the XMCD spectra at
T = 6 K and B = 5 T. The parameters used to obtain the fits to
Eq. (2) are collected in Table 1.
Low Temperature Physics/Fizika Nizkikh Temperatur, 2017, v. 43, No. 8 1191
Juan Bartolomé, Fernando Bartolomé, Luis Miguel García, Thomas Gredig, Ivan K. Schuller, and Julio C. Cezar
Discussion
The XMCD experiment, performed in a magnetic field
parallel to the incoming x-ray beam at an incident angle γ,
provides the projection of the Fe magnetic moment along
the direction of the magnetic field ( ) / .m Hγ = ⋅H m The
FePc molecule symmetry may be approximated to D4h,
thus the molecular z axis corresponds to the fourfold axis,
while the two perpendicular axes x and y, are assumed to
be identical.
In what follows we assume the intermolecular magnetic
interactions to be negligible. Our sample in the present work
can be modeled as consisting of chains of parallel stacked
molecules along the b axis, with their z axis tilted by 26.5°
with respect to the b axis. The chains are parallel to the sub-
strate (see Fig. 2(a)) and form structural domains, which
give rise to a well defined x-ray diffraction pattern [4]. The
direction of the chain b axes are distributed according to the
mosaicity of the substrate. Thus we assume a statistically
random distribution of b axes in angle around the normal to
the substrate N, but always parallel to the substrate (see
Fig. 2(a)). In addition, each molecular plane forms an angle
within the range 63.5° < β < 90° with respect to N, depen-
ding on the orientation of the chain a axis. For completeness
sake, in Eq. (1) we show the statistical average of the mag-
netization as a function of incident angle for a fixed β angle.
Using /L z Bm L= −〈 〉µ the orbital moment and
eff 7 ,S S Tm m m= − where 2 /S z Bm S= − 〈 〉µ is the spin
moment and 2 /T Bm T= − 〈 〉µ is the intra-atomic dipolar
moment, one obtains
( ) ( )2 2 2sin cos cosy zm m mγ = β + β γ +
( )2 2 21 cos sin sin
2
x y zm m m+ + β + β γ . (1)
The angle between the molecular z axis and N is β ≈ 90°,
while maintaining the herringbone structure on the plane
parallel to the substrate (see Fig. 2(a)) [4]. With the appro-
ximation x ym m= , Eq. (1) becomes
( ) ( )2 21cos sin
2
x x zm m m mγ = γ + + γ . (2)
The film average orbital magnetic moment per Fe atom is
larger for normal incidence than in the direction of the sub-
strate plane ||( ),L Lm m⊥ > thus the film with standing confi-
guration has a film anisotropy perpendicular to the substra-
te, in contrast to the laying configuration which is parallel
to the substrate ||( ).L Lm m⊥ <
The data in Fig. 5 have been fitted to Eq. (2) for each
component, orbital or effective spin. The resulting moment
components are collected in Tables 1 and 2.
The values of the single molecule magnetic moment pa-
rameters in the standing configuration are very similar to
those found for the laying one. Actually, the orbital to spin
ratio /xy
SLm m is the same for both configurations, within
experimental errors. This is an important result since it
indicates that the orbital moment is very large, stemming
from unquenched orbital moment due to the orbital
degeneracy of the eg doublet at the Fermi surface [2]. We
note here that the maximum orbital magnetic moment
0.50(4)z
Lm ≈ is several times larger than predicted from
DFT calculations [19].
Besides, the intra-atomic magnetic dipolar component
differs between the two configurations by a factor close to
three. This difference is probably related to the differences
in the position of the Fe atom and orientation of each
molecule with respect to their adjacent ones.
In this respect, the chains in the standing configuration
order within the chain in the α-phase type of herringbone
structure, in which the Fe atom in one molecule is near the
center of one of the pyrrolic rings of the adjacent molecule
at each side [4]. On the other hand, we proved earlier by
scanning tunneling microscopy and x-ray absorption at the
Fe-K-edge that in the laying configuration each Fe atom
has, as nearest neighbor atom in the adjacent molecules,
the N atom of the pyrrolic ring closest to the central Fe (so
called TF phase) [20]. Therefore, the first coordination of
Fe is different in the two configurations, which explains
the very different z
Tm ’s derived from experiment.
Table 1. The four magnetic moment parameters in units of µB
determined with respect to the directions N (m⊥) and parallel to
the substrate (m||) for the FePc films in standing and laying con-
figurations
Configuration ||
Lm Lm⊥ eff , ||
Sm eff ,
Sm ⊥
FePc on Si(110)
Standing conf.
0.37(5) 0.50(4) 0.55(5) 0.70(5)
FePc on Au
Laying conf.
0.53(5) 0.29(4) 0.69(5) 0.10(5)
Table 2. First entry: the four adjusted magnetic moment parameters in units of µB, obtained from the fit of the XMCD sum rule results to
Eq. (2), and calculated orbital to spin moment ratio. Second entry: same parameters for FePc film deposited in the laying configuration [2]
Configuration z
Lm xy
Lm mS z
Tm /xy
SLm m
FePc on Si(110) Standing conf. 0.24(5) 0.50(4) 0.59(5) 0.027(5) 0.86(4)
FePc on Au Laying conf. 0.29(5) 0.53(4) 0.64(5) 0.074(5) 0.83(4)
1192 Low Temperature Physics/Fizika Nizkikh Temperatur, 2017, v. 43, No. 8
Magnetic anisotropy in Fe phthalocyanine film deposited on Si(110) substrate: standing configuration
It is interesting to note that the single ion planar
anisotropy caused by spin-orbit coupling is actually enhanced
in the standing configuration. Indeed, from the values for the
orbital and dipolar moments, following Refs. 21, 22, one may
calculate the spin-orbit contribution to the anisotropy energy
( ) 2
33
ex
21 3
2 2
4
zxyz d Td L L
SO
B B
m Am mGE
H E
× ξ +ξ − × ∆ = − + µ ∆ µ
.
(3)
With G/H ≈ 0.2 for transition metals, 3dξ = 0.05 eV is
the spin-orbit coupling constant in Fe, ex 1.1 eV∆ = is the
energy shift between the majority and minority states, and A
negligible, as described in Ref. 2, one obtains ∆ESQ = 7·10–5
and 4.5·10–4 eV/Fe atom for the laying and standing
configurations, respectively. That is, the planar anisotropy
(positive ∆ESQ) is actually enhanced by spin-orbit coupling
in the standing configuration with respect to the laying one.
Conclusions
The present results for the standing configuration
confirm the extraordinarily large unquenched orbital mo-
ment of FePc single molecules due to the orbital degeneracy
of the eg doublet near the Fermi surface that was found in
the laying configuration. The FePc single molecule magnetic
anisotropy in the standing configuration is planar and nearly
identical to that found for the FePc in the laying configurati-
on. In contrast, the standing configuration differs from the
laying one in showing perpendicular anisotropy as a film.
This is caused by the single ion FePc magnetic planar
anisotropy and the statistical average of the molecule mo-
ments when the molecule planes are perpendicular to the
substrate in the standing configuration.
Acknowledgments
The financial support of the Spanish MINECO
MAT2014-53921-R and Aragonese DGA-IMANA E34,
both cofunded by Fondo Social Europeo and European
Union FEDER funds is acknowledged. T.G. acknowledg-
es support from the National Science Foundation (NSF)
DMR-0847552 and the W.M. Keck Foundation. The
XMCD experiments were performed at the ID08 (now
ID32) beamline of the ESRF, experiment HE2486. This is a
highly collaborative research. The experiments were
conceived jointly, the data was extensively debated and the
paper was written by multiple iteration between all the
coauthors. Samples were fabricated, characterized and
prepared at UCSD (T.G. and I.K.S.). The research at UCSD
was supported by the Office of Basic Energy Science, U.S.
Department of Energy, BES-DMS funded by the Depart-
ment of Energy’s Office of Basic Energy Science, DMR
under grant DE FG02 87ER-45332.
1. M. Evangelisti, J. Bartolomé, L.J. de Jongh, and G. Filoti,
Phys. Rev. B 66, 144410 (2002).
2. J. Bartolomé, F. Bartolomé, L.M. García, G. Filoti, T. Gredig,
C.N. Colesniuc, I.K. Schuller, and J.C. Cezar, Phys. Rev. B 81,
195405 (2010).
3. J. Bartolomé, C. Monton, and I.K. Schuller, Magnetism of
Metal Phthalocyanines, in Molecular Magnets: Physics and
Applications, J. Bartolomé, F. Luis, and J.F. Fernández
(eds.), Berlin: Springer (2014), p. 221.
4. T. Gredig, K.P. Gentry, C.N. Colesniuc, and I.K. Schuller,
J. Mater. Sci. 45, 5032 (2010).
5. T. Takami, C. Carrizales, and K.W. Hipps, Surf. Sci. 603,
3201 (2009).
6. K. Manandhar, K.T. Park, S. Ma, and J. Hrbek, Surf. Sci.
603, 636 (2009).
7. A. Mugarza, R. Robles, C. Krull, R. Korytár, N. Lorente, and
P. Gambardella, Phys. Rev. B 85 155437 (2012).
8. E. Annese, J. Fujii, I. Vobornik, and G. Rossi, J. Phys.
Chem. C 111, 17409 (2011).
9. C. Miller, A. Sharoni, G. Liu, C. Colesniuc, B. Fruhberger,
and I. Schuller, Phys. Rev. B 72, 104113 (2005).
10. K.P. Gentry, T. Gredig, and I.K. Schuller, Phys. Rev. B 80,
174118 (2009).
11. T. Gredig, C.N. Colesniuc, S.A. Crooker, and I.K. Schuller,
Phys. Rev. B 86, 14409 (2012).
12. P.D. Ekstrand, D.J. Javier, and T. Gredig, Phys. Rev. B 95,
14406 (2017).
13. H. Peisert, T. Schwieger, J.M. Auerhammer, M. Knupfer,
M.S. Golden, J. Fink, P.R. Bressler, and M. Mast, J. Appl.
Phys. 90, 466 (2001).
14. C. Monton, I. Valmianski, and I.K. Schuller, Appl. Phys.
Lett. 101, 133304 (2012).
15. G. Filoti, M.D. Kuz’min, and J. Bartolomé, Phys. Rev. B 74,
134420 (2006).
16. G. Liu, T. Gredig, and I.K. Schuller, Europhys. Lett. 83,
56001 (2008).
17. B.T. Thole, P. Carra, F. Sette, and G. Van Der Laan, Phys.
Rev. Lett. 68, 1943 (1992).
18. P. Carra, B.T. Thole, M. Altarelli, and X. Wang, Phys. Rev.
Lett. 70, 694 (1993).
19. J. Wang, Y. Shi, J. Cao, and R. Wu, Appl. Phys. Lett. 94,
122502 (2009).
20. F. Bartolomé, O. Bunau, L.M. García, C.R. Natoli, M.
Piantek, J.I. Pascual, I.K. Schuller, T. Gredig, F. Wilhelm,
A. Rogalev, and J. Bartolomé, J. Appl. Phys. 117, 17A735
(2015).
21. G. Van Der Laan, J. Phys.: Condens. Matter 10, 3239
(1999).
22. K. Mamiya, T. Koide, Y. Ishida, Y. Osafune, A. Fujimori,
Y. Suzuki, T. Katayama, and S. Yuasa, Radiat. Phys. Chem.
75, 1872 (2006).
Low Temperature Physics/Fizika Nizkikh Temperatur, 2017, v. 43, No. 8 1193
Introduction
Experimental details
XLPA and XMCD results
Discussion
Conclusions
Acknowledgments
|