Crystalline films of La0.65Pb0.35MnO3 grown on (100) LaAlO 3 substrates by rf sputtering have been investigated using magnetic circular dichroism and inverse photoemission spectroscopy. We find evidence for strong hybridization between unoccupied levels associated with Mn 3d and O 2p states. The oxygen atoms  pick-up  a small magnetic moment through hybridization with Mn. ©2000 American Institute of Physic

Borca, C.N.

Cheng, R.H.

Dowben, Peter A.

Idzerda, Y.U.

Liou, Sy_Hwang

Stadler, Shane

Xu, Q.L.

English

UNL | Libraries

University of Nebraska - Lincoln 
DigitalCommons@University of Nebraska - Lincoln 
Peter Dowben Publications Research Papers in Physics and Astronomy 
5-1-2000 
Origin of the magnetic moments in La0.65Pb0.35MnO3 epitaxial 
thin films 
C.N. Borca 
University of Nebraska-Lincoln 
R.H. Cheng 
University of Nebraska-Lincoln 
Q.L. Xu 
University of Nebraska-Lincoln 
Sy_Hwang Liou 
University of Nebraska-Lincoln, sliou@unl.edu 
Shane Stadler 
Naval Research Laboratory, NSLS, Upton, New York, stadler@phys.lsu.edu 
See next page for additional authors 
Follow this and additional works at: https://digitalcommons.unl.edu/physicsdowben 
 Part of the Physics Commons 
Borca, C.N.; Cheng, R.H.; Xu, Q.L.; Liou, Sy_Hwang; Stadler, Shane; Idzerda, Y.U.; and Dowben, Peter A., 
"Origin of the magnetic moments in La0.65Pb0.35MnO3 epitaxial thin films" (2000). Peter Dowben 
Publications. 32. 
https://digitalcommons.unl.edu/physicsdowben/32 
This Article is brought to you for free and open access by the Research Papers in Physics and Astronomy at 
DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Peter Dowben Publications 
by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. 
Authors 
C.N. Borca, R.H. Cheng, Q.L. Xu, Sy_Hwang Liou, Shane Stadler, Y.U. Idzerda, and Peter A. Dowben 
This article is available at DigitalCommons@University of Nebraska - Lincoln: https://digitalcommons.unl.edu/
physicsdowben/32 
Origin of the magnetic moments in La0.65Pb0.35MnO3 epitaxial thin films
C. N. Borca, R. H. Cheng, Q. L. Xu, and S. H. Liou
Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588-0111
Shane Stadler
Naval Research Laboratory, NSLS, Upton, New York 11973
Y. U. Idzerda
Naval Research Laboratory, Material Physics Branch, Washington, DC 20375
P. A. Dowbena)
Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588-0111
Crystalline films of La0.65Pb0.35MnO3 grown on ~100! LaAlO 3 substrates by rf sputtering have been
investigated using magnetic circular dichroism and inverse photoemission spectroscopy. We find
evidence for strong hybridization between unoccupied levels associated with Mn 3d and O 2p states.
The oxygen atoms ‘‘pick-up’’ a small magnetic moment through hybridization with Mn. © 2000
American Institute of Physics. @S0021-8979~00!41908-0#
I. INTRODUCTION
The observation of colossal magnetoresistance ~CMR! in
manganese oxides crystallizing in the perovskite structure
has generated considerable interest in the physical properties
of the class of compound, particularly the interplay of struc-
ture, magnetism, and electronic transport. The
La0.65Pb0.35MnO3 system has been given scant attention and
few studies of the epitaxial thin films exist.1 Recent results2
have shown that the magnetoresistance ~MR! in this system
can be optimized so that the magnitude of the MR is more
than 40% at 300 K. As with all CMR manganese perovs-
kites, one issue of considerable interest is the origin of the
coupling and medium of exchange as well as the origin of
the moment. The present article reports on the magnetic
properties obtained from magnetic circular dichroism ~MCD!
and inverse photoemission spectroscopy performed on
single-crystal thin films of La0.65Pb0.35MnO3.
II. SAMPLE PREPARATION AND EXPERIMENTAL
DETAILS
The La0.65Pb0.35MnO3 films, with a nominal thickness of
1000 Å, were grown on ~100! LaAlO3 substrates by rf sput-
tering in a 4:1 argon/oxygen atmosphere maintained at 15
mTorr. The samples were subsequently annealed in two steps
in order to prevent Pb evaporation: at a temperature of
650 °C for 10 h and at 850 °C for 2 h in an oxygen pressure
of 1 atm. The bulk chemical composition was determined
from energy dispersive analysis of the x-ray emission. The
orientation ~100! and the epitaxial characteristics were deter-
mined by x-ray diffraction2 and low electron energy diffrac-
tion.
The x-ray absorption spectroscopy ~XAS! and MCD
spectra were recorded by monitoring the sample current,
which corresponds to the total electron yield. For magnetiz-
ing the sample, a 400 Oe pulse field was applied along the
in-plane easy axis. The spectra for two different helicities
were recorded by alternating the magnetization at every pho-
ton energy. In the total electron yield mode, the SAX spectra
probes approximately 100 Å in depth, which is an interme-
diate length scale between the bulk and the surface bound-
ary.
The inverse photoemission data were obtained on a
home made system by using variable energy electrons and an
ultraviolet detector ~Geiger–Muller!. In our scheme, 9.8 eV
photons were detected with the Geiger–Muller tube with
;400 meV bandwidth. The overall energy resolution in in-
verse photoemission was ;450 meV.
Neutron powder diffraction patterns show that the
La0.65Pb0.35MnO3 is single-phase polycrystalline with a
rhombohedral R3c structure. The lattice parameters are a
5b55.51 Å and c513.38 Å, and the angles a5b590°,g
5120° at room temperature. The same crystallographic
group symmetry was reported in Refs. 3–5.
III. EXPERIMENTAL RESULTS AND DISCUSSIONS
The XAS and MCD spectra for the MN L-edge at dif-
ferent temperatures is shown in Figs. 1~a! and 1~b!, respec-
tively. As can be seen in panel ~a! of Fig. 1, the L2,3 edges
are very well defined and exhibit sharp peaks. These spectra
are comparable with the Mn 2p core levels obtained using
x-ray photoemission spectroscopy,6 which can only probe
5–15 Å from the surface. The conclusion here is that the
sample is relatively free of defects and homogenous, except
in the surface region, which is compositionally different
from the bulk. The surface region, discussed in detail
elsewhere,6 exhibits Mn 2p binding energies for
La0.65Pb0.35MnO3 consistent with a Mn31 state rather than a
Mn41 state. The MCD spectra presented in panel ~b! of Fig.
1 is given by the difference between the absorption signals
having the photon helicity parallel and respectively, antipar-
allel to the saturation magnetization. The MCD anisotropy,
the difference divided by the sum of the two absorption sig-
nals, is proportional to the Mn magnetic moment. The tem-a!Electronic mail: pdowben@unl.edu
JOURNAL OF APPLIED PHYSICS VOLUME 87, NUMBER 9 1 MAY 2000
56060021-8979/2000/87(9)/5606/3/$17.00 © 2000 American Institute of Physics
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perature dependence of the MCD anisotropy is presented in
Fig. 2~b!. The magnetic moment decreases smoothly with
increasing temperature without any change in the MCD line
shape.
The magnetization of the bulk measured with a super-
conducting quantum interference device ~SQUID! is shown
in Fig. 2~a!. By comparison, the magnetization dependence
obtained by MCD deviates from the bulk, and the Curie tem-
perature determined from the Mn MCD signal is lower than
the bulk TC . This deviation can be attributed to composi-
tional differences at the surface boundary layer.6
In Fig. 3~b! we show the temperature dependence of the
O 1s XAS spectra of La0.65Pb0.35MnO3 single-crystal thin
film. The two features in the spectrum represent the hybrid-
ization band between O 2p and Mn 3d/4s unoccupied levels.
Panel ~c! in Fig. 3 shows the MCD signal at 90 K. It is clear
that the O atoms become ferromagnetically aligned with a
small, but not negligible, magnetic moment. The temperature
dependence of the normalized O moment is presented in Fig.
2~c!.
The electronic valence band structure of the manganese
transition metal oxides, La0.65A0.35MnO3 ~A5Ca, Sr, and
FIG. 1. X-ray absorption ~a! and the magnetic circular dichroism ~MCD!
spectra ~b! at Mn L-edge. In panel ~a! the absorption spectra, at 80 K, are
presented for the photon helicity parallel ~continuous line! and antiparallel
~dotted line! with the magnetization direction. The photon incident angle
and the degree of circular polarization were taken into account for the spec-
tra.
FIG. 2. ~a! Temperature dependence of the La0.65Pb0.35MnO3 bulk magne-
tization measured by SQUID. ~b! Temperature dependence of the MCD
anisotropy of Mn L-absorption edge, which is proportional to the MN mag-
netic moment in the surface region. ~c! Temperature dependence of the
MCD signal of oxygen 1s edge from the film surface region.
FIG. 3. Normalized inverse photoemission spectrum taken at 300 K ~a!
oxygen 1s XAS ~b! and MCD ~c! spectra at 90 K. The data in ~b! and ~c! are
normalized with respect to the photon incident angle and the degree of
circular polarization.
5607J. Appl. Phys., Vol. 87, No. 9, 1 May 2000 Borca et al.
Downloaded 06 Sep 2006 to 129.93.16.206. Redistribution subject to AIP license or copyright, see http://jap.aip.org/jap/copyright.jsp
Ba!, is mostly dominated with the extensively hybridized Mn
3d –O 2pstates.7–20 Nonetheless, the inverse photoemission
spectra for the conduction band structure are dominated by
two clear features, as shown in Fig. 3~a!. There are two main
features at 3 and 7 eV above the Fermi level and a satellite
about 0.7 eV above EF .The first two features ~at 0.7 and 3
eV above the Fermi level! are generally considered to corre-
spond to the nonbonding or antibonding-like states with Mn
3d – O 2p hybridized character.20 The higher energy feature
at 7 eV above the Fermi level corresponds to the La 4 f
states.20,21 The major intensity from the antibonding-like
states of the Mn 3d –O 2p are positioned at approximately 2
eV above the Fermi level for both La0.65Ca0.35MnO3 and
La0.65Ba0.35MnO3 while the antibonding-like states of the Mn
3d –O 2p hybridization states for the La0.65Sr0.35MnO3 is at
about 4 eV above the Fermi level.22 The La0.65Pb0.35MnO3
system is very similar in character with La0.65Ca0.35MnO3
and La0.65Ba0.35MnO3 as seen in Fig. 3~a!. The feature at 7
eV in the conduction band inverse photoemission spectra,
corresponding to the La 4 f states,20–22 is clearly observed in
the conduction band of La0.65A0.35MnO3 ~A5Ca, Ba, and Sr!
and is also observed for La0.65Pb0.35MnO3 both in the inverse
photoemission and XAS O (1s) spectra ~Fig. 3!.
The unoccupied electronic structure of La0.65Pb0.35MnO3
films dominates the XAS spectra shown in Fig. 3~b!. From
the comparison of the inverse photoemission with the XAS
spectra we can use the above assignments of the unoccupied
electronic structure to postulate the origin of the oxygen
MCD signal. It is clear that most of the oxygen moment
arises in the unoccupied levels associated with the Mn 3d –O
2p hybridization states. There is far less signal associated
with the La–O states. This is consistent with the fact that we
obtained no MCD signal from the La or Pb cores.
IV. CONCLUSIONS
We have found that one can obtain a large MCD signal
in Pb-doped LaMnO3 films. From x-ray MCD we find that
most of the magnetic moment resides in the Mn atoms. The
oxygen atoms have a small moment that is ferromagnetically
aligned with the Mn atoms, and it has its origin in the Mn–O
hybridized states, not in the Pb/La–O plane.
ACKNOWLEDGMENTS
This work was supported by NSF through Grant No.
DMR-98-02126 and the Center for Materials Research and
Analysis ~CMRA! at the University of Nebraska.
1 J.-Q. Wang, G.-J. Cui, T. Tamagawa, B. L. Halpern, and R. C. Barker,
Appl. Phys. Lett. 71, 3418 ~1997!.
2 Q. L. Xu, M. T. Liu, Y. Liu, C. N. Borca, H. Dulli, P. A. Dowben, and
S.-H. Liou, Mater. Res. Soc. Symp. Proc. ~in press!.
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Phys. D 28, 1743 ~1995!.
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3036 ~1998!.
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85, 5384 ~1999!.
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proceedings!.
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75, 3910 ~1995!.
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Correlated Metals, Series in Solid-State Sciences, Vol. 119 ~Springer,
New York, 1995!, p. 126.
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san, Nature ~London! 392, 794 ~1998!.
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5608 J. Appl. Phys., Vol. 87, No. 9, 1 May 2000 Borca et al.
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Origin of the magnetic moments in La\u3csub\u3e0.65\u3c/sub\u3ePb\u3csub\u3e0.35\u3c/sub\u3eMnO\u3csub\u3e3\u3c/sub\u3e epitaxial thin films

DigitalCommons@University of Nebraska

University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Peter Dowben Publications Research Papers in Physics and Astronomy 5-1-2000 Origin of the magnetic moments in La0.65Pb0.35MnO3 epitaxial thin films C.N. Borca University of Nebraska-Lincoln R.H. Cheng University of Nebraska-Lincoln Q.L. Xu University of Nebraska-Lincoln Sy_Hwang Liou University of Nebraska-Lincoln, sliou@unl.edu Shane Stadler Naval Research Laboratory, NSLS, Upton, New York, stadler@phys.lsu.edu See next page for additional authors Follow this and additional works at: https://digitalcommons.unl.edu/physicsdowben  Part of the Physics Commons Borca, C.N.; Cheng, R.H.; Xu, Q.L.; Liou, Sy_Hwang; Stadler, Shane; Idzerda, Y.U.; and Dowben, Peter A., "Origin of the magnetic moments in La0.65Pb0.35MnO3 epitaxial thin films" (2000). Peter Dowben Publications. 32. https://digitalcommons.unl.edu/physicsdowben/32 This Article is brought to you for free and open access by the Research Papers in Physics and Astronomy at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Peter Dowben Publications by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Authors C.N. Borca, R.H. Cheng, Q.L. Xu, Sy_Hwang Liou, Shane Stadler, Y.U. Idzerda, and Peter A. Dowben This article is available at DigitalCommons@University of Nebraska - Lincoln: https://digitalcommons.unl.edu/physicsdowben/32 Origin of the magnetic moments in La0.65Pb0.35MnO3 epitaxial thin filmsC. N. Borca, R. H. Cheng, Q. L. Xu, and S. H. LiouDepartment of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588-0111Shane StadlerNaval Research Laboratory, NSLS, Upton, New York 11973Y. U. IdzerdaNaval Research Laboratory, Material Physics Branch, Washington, DC 20375P. A. Dowbena)Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588-0111Crystalline films of La0.65Pb0.35MnO3 grown on ~100! LaAlO 3 substrates by rf sputtering have beeninvestigated using magnetic circular dichroism and inverse photoemission spectroscopy. We findevidence for strong hybridization between unoccupied levels associated with Mn 3d and O 2p states.The oxygen atoms ‘‘pick-up’’ a small magnetic moment through hybridization with Mn. © 2000American Institute of Physics. @S0021-8979~00!41908-0#I. INTRODUCTIONThe observation of colossal magnetoresistance ~CMR! inmanganese oxides crystallizing in the perovskite structurehas generated considerable interest in the physical propertiesof the class of compound, particularly the interplay of struc-ture, magnetism, and electronic transport. TheLa0.65Pb0.35MnO3 system has been given scant attention andfew studies of the epitaxial thin films exist.1 Recent results2have shown that the magnetoresistance ~MR! in this systemcan be optimized so that the magnitude of the MR is morethan 40% at 300 K. As with all CMR manganese perovs-kites, one issue of considerable interest is the origin of thecoupling and medium of exchange as well as the origin ofthe moment. The present article reports on the magneticproperties obtained from magnetic circular dichroism ~MCD!and inverse photoemission spectroscopy performed onsingle-crystal thin films of La0.65Pb0.35MnO3.II. SAMPLE PREPARATION AND EXPERIMENTALDETAILSThe La0.65Pb0.35MnO3 films, with a nominal thickness of1000 Å, were grown on ~100! LaAlO3 substrates by rf sput-tering in a 4:1 argon/oxygen atmosphere maintained at 15mTorr. The samples were subsequently annealed in two stepsin order to prevent Pb evaporation: at a temperature of650 °C for 10 h and at 850 °C for 2 h in an oxygen pressureof 1 atm. The bulk chemical composition was determinedfrom energy dispersive analysis of the x-ray emission. Theorientation ~100! and the epitaxial characteristics were deter-mined by x-ray diffraction2 and low electron energy diffrac-tion.The x-ray absorption spectroscopy ~XAS! and MCDspectra were recorded by monitoring the sample current,which corresponds to the total electron yield. For magnetiz-ing the sample, a 400 Oe pulse field was applied along thein-plane easy axis. The spectra for two different helicitieswere recorded by alternating the magnetization at every pho-ton energy. In the total electron yield mode, the SAX spectraprobes approximately 100 Å in depth, which is an interme-diate length scale between the bulk and the surface bound-ary.The inverse photoemission data were obtained on ahome made system by using variable energy electrons and anultraviolet detector ~Geiger–Muller!. In our scheme, 9.8 eVphotons were detected with the Geiger–Muller tube with;400 meV bandwidth. The overall energy resolution in in-verse photoemission was ;450 meV.Neutron powder diffraction patterns show that theLa0.65Pb0.35MnO3 is single-phase polycrystalline with arhombohedral R3c structure. The lattice parameters are a5b55.51 Å and c513.38 Å, and the angles a5b590°,g5120° at room temperature. The same crystallographicgroup symmetry was reported in Refs. 3–5.III. EXPERIMENTAL RESULTS AND DISCUSSIONSThe XAS and MCD spectra for the MN L-edge at dif-ferent temperatures is shown in Figs. 1~a! and 1~b!, respec-tively. As can be seen in panel ~a! of Fig. 1, the L2,3 edgesare very well defined and exhibit sharp peaks. These spectraare comparable with the Mn 2p core levels obtained usingx-ray photoemission spectroscopy,6 which can only probe5–15 Å from the surface. The conclusion here is that thesample is relatively free of defects and homogenous, exceptin the surface region, which is compositionally differentfrom the bulk. The surface region, discussed in detailelsewhere,6 exhibits Mn 2p binding energies forLa0.65Pb0.35MnO3 consistent with a Mn31 state rather than aMn41 state. The MCD spectra presented in panel ~b! of Fig.1 is given by the difference between the absorption signalshaving the photon helicity parallel and respectively, antipar-allel to the saturation magnetization. The MCD anisotropy,the difference divided by the sum of the two absorption sig-nals, is proportional to the Mn magnetic moment. The tem-a!Electronic mail: pdowben@unl.eduJOURNAL OF APPLIED PHYSICS VOLUME 87, NUMBER 9 1 MAY 200056060021-8979/2000/87(9)/5606/3/$17.00 © 2000 American Institute of PhysicsDownloaded 06 Sep 2006 to 129.93.16.206. Redistribution subject to AIP license or copyright, see http://jap.aip.org/jap/copyright.jspperature dependence of the MCD anisotropy is presented inFig. 2~b!. The magnetic moment decreases smoothly withincreasing temperature without any change in the MCD lineshape.The magnetization of the bulk measured with a super-conducting quantum interference device ~SQUID! is shownin Fig. 2~a!. By comparison, the magnetization dependenceobtained by MCD deviates from the bulk, and the Curie tem-perature determined from the Mn MCD signal is lower thanthe bulk TC . This deviation can be attributed to composi-tional differences at the surface boundary layer.6In Fig. 3~b! we show the temperature dependence of theO 1s XAS spectra of La0.65Pb0.35MnO3 single-crystal thinfilm. The two features in the spectrum represent the hybrid-ization band between O 2p and Mn 3d/4s unoccupied levels.Panel ~c! in Fig. 3 shows the MCD signal at 90 K. It is clearthat the O atoms become ferromagnetically aligned with asmall, but not negligible, magnetic moment. The temperaturedependence of the normalized O moment is presented in Fig.2~c!.The electronic valence band structure of the manganesetransition metal oxides, La0.65A0.35MnO3 ~A5Ca, Sr, andFIG. 1. X-ray absorption ~a! and the magnetic circular dichroism ~MCD!spectra ~b! at Mn L-edge. In panel ~a! the absorption spectra, at 80 K, arepresented for the photon helicity parallel ~continuous line! and antiparallel~dotted line! with the magnetization direction. The photon incident angleand the degree of circular polarization were taken into account for the spec-tra.FIG. 2. ~a! Temperature dependence of the La0.65Pb0.35MnO3 bulk magne-tization measured by SQUID. ~b! Temperature dependence of the MCDanisotropy of Mn L-absorption edge, which is proportional to the MN mag-netic moment in the surface region. ~c! Temperature dependence of theMCD signal of oxygen 1s edge from the film surface region.FIG. 3. Normalized inverse photoemission spectrum taken at 300 K ~a!oxygen 1s XAS ~b! and MCD ~c! spectra at 90 K. The data in ~b! and ~c! arenormalized with respect to the photon incident angle and the degree ofcircular polarization.5607J. Appl. Phys., Vol. 87, No. 9, 1 May 2000 Borca et al.Downloaded 06 Sep 2006 to 129.93.16.206. Redistribution subject to AIP license or copyright, see http://jap.aip.org/jap/copyright.jspBa!, is mostly dominated with the extensively hybridized Mn3d –O 2pstates.7–20 Nonetheless, the inverse photoemissionspectra for the conduction band structure are dominated bytwo clear features, as shown in Fig. 3~a!. There are two mainfeatures at 3 and 7 eV above the Fermi level and a satelliteabout 0.7 eV above EF .The first two features ~at 0.7 and 3eV above the Fermi level! are generally considered to corre-spond to the nonbonding or antibonding-like states with Mn3d – O 2p hybridized character.20 The higher energy featureat 7 eV above the Fermi level corresponds to the La 4 fstates.20,21 The major intensity from the antibonding-likestates of the Mn 3d –O 2p are positioned at approximately 2eV above the Fermi level for both La0.65Ca0.35MnO3 andLa0.65Ba0.35MnO3 while the antibonding-like states of the Mn3d –O 2p hybridization states for the La0.65Sr0.35MnO3 is atabout 4 eV above the Fermi level.22 The La0.65Pb0.35MnO3system is very similar in character with La0.65Ca0.35MnO3and La0.65Ba0.35MnO3 as seen in Fig. 3~a!. The feature at 7eV in the conduction band inverse photoemission spectra,corresponding to the La 4 f states,20–22 is clearly observed inthe conduction band of La0.65A0.35MnO3 ~A5Ca, Ba, and Sr!and is also observed for La0.65Pb0.35MnO3 both in the inversephotoemission and XAS O (1s) spectra ~Fig. 3!.The unoccupied electronic structure of La0.65Pb0.35MnO3films dominates the XAS spectra shown in Fig. 3~b!. Fromthe comparison of the inverse photoemission with the XASspectra we can use the above assignments of the unoccupiedelectronic structure to postulate the origin of the oxygenMCD signal. It is clear that most of the oxygen momentarises in the unoccupied levels associated with the Mn 3d –O2p hybridization states. There is far less signal associatedwith the La–O states. This is consistent with the fact that weobtained no MCD signal from the La or Pb cores.IV. CONCLUSIONSWe have found that one can obtain a large MCD signalin Pb-doped LaMnO3 films. From x-ray MCD we find thatmost of the magnetic moment resides in the Mn atoms. Theoxygen atoms have a small moment that is ferromagneticallyaligned with the Mn atoms, and it has its origin in the Mn–Ohybridized states, not in the Pb/La–O plane.ACKNOWLEDGMENTSThis work was supported by NSF through Grant No.DMR-98-02126 and the Center for Materials Research andAnalysis ~CMRA! at the University of Nebraska.1 J.-Q. Wang, G.-J. Cui, T. Tamagawa, B. L. Halpern, and R. C. Barker,Appl. Phys. Lett. 71, 3418 ~1997!.2 Q. L. Xu, M. T. Liu, Y. Liu, C. N. Borca, H. Dulli, P. A. Dowben, andS.-H. Liou, Mater. Res. Soc. Symp. Proc. ~in press!.3 R. Mahendiran, R. Mahesh, A. K. Raychaudhuri, and C. N. R. Rao, J.Phys. D 28, 1743 ~1995!.4 G. Ji, X. J. Fan, J. H. Zhang, C. S. Xiong, and X. G. Li, J. Phys. D 31,3036 ~1998!.5 R.-M. Thomas, V. Skumryev, S. Wirth, and J. M. D. Coey, J. Appl. Phys.85, 5384 ~1999!.6 C. N. Borca, D. Ristoiu, Q. L. Zu, S.-H. Liou, and P. A. Dowben ~theseproceedings!.7 J. M. D. 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Origin of the magnetic moments in La\u3csub\u3e0.65\u3c/sub\u3ePb\u3csub\u3e0.35\u3c/sub\u3eMnO\u3csub\u3e3\u3c/sub\u3e epitaxial thin films

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