Supplementary
Unraveling how electronic and spin structures control macroscopic properties
of manganite ultra-thin films
Xinmao Yin1,2, Muhammad Aziz Majidi1,2, Xiao Chi1,2, Peng Ren3, Lu You3, Natalia Palina2,
Xiaojiang Yu2, Caozheng Diao2, Daniel Schmidt2, Baomin Wang4, Ping Yang2, Mark B.H.
Breese1,2, Junling Wang3,†, Andrivo Rusydi1,2,‡
1
NUSSNI-NanoCore, Department of Physics, National University of Singapore (NUS), 2
Science Drive 3, 117542, Singapore
2
Singapore Synchrotron Light Source (SSLS), National University of Singapore (NUS), 5
Research Link, 117603, Singapore
3
School of Materials Science and Engineering, Nanyang Technological University (NTU),
Nanyang Avenue, 639798, Singapore
4
Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Material Technology
and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang, 315201, P. R. China
E-mail: †phyandri@nus.edu.sg; ‡jlwang@ntu.edu.sg;
Page 1 of 23
Supplementary Figures
Supplementary Figure 1 | L-scan in high-resolution X-ray diffractometry (HR-XRD)
measurements. L-scan corresponding the normal of La0.7Sr0.3MnO3 (LSMO) film on [110]orthorhombic oriented DyScO3 (DSO) substrate. The arrows indicate thickness fringes, showing
a coherent interface between the film and substrate, whose distance can be used to estimate the
layer thickness. The directions of the reciprocal coordinates H, K and L are corresponding to
[001], [1-10] and [110] of DSO respectively.
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Supplementary Figure 2 | Reciprocal space mappings (RSM) using high-resolution X-ray
diffractometry (HR-XRD) measurements. RSMs around (a) (002)HL, (b) (002)KL, (c) ( 03)HL,
and (d) (013)KL are shown for La0.7Sr0.3MnO3 (LSMO) film on DyScO3 (DSO) substrate. The
directions of the reciprocal coordinates H, K and L correspond to [001], [1-10] and [110] of DSO
respectively.
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Supplementary Figure 3 | Reciprocal space mappings (RSMs) using high-resolution X-ray
diffractometry (HR-XRD) measurements. RSMs around (a) (002)HL, (b) (002)KL, (c) ( 03)HL,
and (d) (013)KL are shown for La0.7Sr0.3MnO3 (LSMO) film on SrTiO3 (STO) substrate. The
directions of the reciprocal coordinates H, K and L correspond to [100], [010] and [001] of STO
respectively.
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Supplementary Figure 4 | Schematic illustration of experimental measurements. Schematic
illustration of the X-ray absorption spectroscopy (XAS), electrical and spectroscopic
ellipsometry experimental measurements.
Supplementary Figure 5 | Ψ and Δ Plots. (a) Ψ and (b) Δ Plots of La0.7Sr0.3MnO3 film on
DyScO3 (DSO) substrate as a function of temperature taken using spectroscopy ellipsometry at
70 degree incident angle from 0.55 eV to 6 eV.
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Supplementary Figure 6 | Ψ and Δ Plots of DyScO3 substrate. (a) Ψ and (b) Δ Plots of
DyScO3 substrate taken using spectroscopic ellipsometry at 65, 70, and 75 degree incident angle
from 0.55 eV to 6 eV at room temperature.
Supplementary Figure 7 | Dielectric function of DyScO3 substrate. Extracted real (ε1) and
imaginary (ε2) parts of the dielectric function of DyScO3 (DSO) substrate from 0.55 eV to 6 eV.
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Supplementary Figure 8 | Dielectric function. (a) Real and (b) imaginary parts of dielectric
constant (ε1(ω) and ε2(ω)) spectra in La0.7Sr0.3MnO3 film as functions of temperature from 0.55
eV to 6 eV. Contour plots of (c) ε1 and (d) ε2 in La0.7Sr0.3MnO3 film as functions of temperature
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and photon energy. (e) Contour plot with color fill of Δσ1 as functions of temperature and photon
energy.
Supplementary Figure 9 | The linear dichroism and polarization-dependent X-ray
absorption spectra taken with E||a and E||c of the La0.7Sr0.3MnO3/ DyScO3 at (a) 80 K and
(b) 300 K. Blue lines: X-ray linear dichroism at 80K and 160K; red and black lines: X-ray
absorption spectra at 80K and 160K.
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Supplementary Figure 10 | X-ray magnetic circular dichroism (XMCD) difference and
their integrated spectra at Mn L3,2-edges. Solid lines: XMCD difference spectra of
La0.7Sr0.3MnO3 film (on DyScO3 (DSO) substrate) at 80K and 160K; dash lines: integrated
XMCD difference spectra at 80K and 160K.
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Supplementary Figure 11 | X-ray magnetic circular dichroism (XMCD) on La0.7Sr0.3MnO3
film (on DyScO3 (DSO) substrate) at Mn L3,2-edges and O K-edge. The grazing incident
(θ=60°) (a-c) Mn L3,2-edges and (d-f)O K-edges x-ray absorption spectra of the La0.7Sr0.3MnO3
film (two opposite magnetization directions relate to the fixed photon helicity (µ+ and µ-) ) at
300K, 160K, and 80K, respectively, with their corresponding XMCD signal (µ+ - µ-) at the
bottom.
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Supplementary Figure 12 | X-ray absorption spectra, transport and magnetic moment of
La0.7Sr0.3MnO3 film on SrTiO3 substrate (LSMO/STO). (a) O K-edge X-ray absorption
spectra of LSMO/STO as a function of temperature for Ec direction. µ(T) is the absorption
spectrum at temperature T. (b) Integrated spectral weight
defined as
in the energy range of 527-533.5 eV for O K-edge spectra and in the energy range of 636-649 eV
for Mn L3-edge spectra for LSMO/STO. (c) Resistivity (ρ) versus temperature curve for
LSMO/STO. (d) The total magnetic moment of LSMO/STO obtained from Mn L-edge XMCD
measurements (see Supplementary Fig. 14).
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Supplementary Figure 13 | Mn L3,2-edge X-ray absorption spectra. Mn L3,2-edge X-ray
absorption spectra of the La0.7Sr0.3MnO3 film on SrTiO3 substrate as a function of temperature
for Ec direction. µ(T) is the absorption spectrum at temperature T.
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Supplementary Figure 14 | X-ray magnetic circular dichroism (XMCD) on ultrathin
La0.7Sr0.3MnO3 film. Grazing incident (θ=60°) Mn L3,2-edges X-ray absorption spectra of the
La0.7Sr0.3MnO3 film on SrTiO3 substrate at (a) 390 K, (b) 300 K, and (c) 80 K (two opposite
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magnetization directions related to the fixed photon helicity (µ+ and µ-) ), respectively, with their
corresponding XMCD signal (µ+ - µ-) at the bottom.
Supplementary Table
Supplementary Table 1 | Magnetic moments. The net spin and orbital magnetic moments (in
units of µB/Mn atom) of La0.7Sr0.3MnO3 film on DyScO3 as a function of temperature.
Temperature (K) mspin(µB)
morb(µB)
morb+mspin(µB)
80 1.011
0.190
1.201
160 0.191
0.011
0.202
Supplementary Table 2 | Magnetic moments. The net spin and orbital magnetic moments (in
units of µB/Mn atom) of La0.7Sr0.3MnO3 film on SrTiO3 as a function of temperature.
Temperature (K) mspin(µB)
morb(µB)
morb+mspin(µB)
80 1.708
0.092
1.8
300 0.726
0.049
0.775
390 0.056
0.003
0.059
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Supplementary methods
High-resolution X-ray Diffraction measurements
To obtain the crystal structure of the La0.7Sr0.3MnO3 (LSMO) film on [110]-orthorhombic
oriented DyScO3 (DSO) substrate (LSMO/DSO), reciprocal space vectors and reciprocal space
mappings are measured by coplanar diffraction geometry. The lattice constants of LSMO are
based on those of DSO substrate, which has a Pnma orthorhombic structure. The lattice
constants of DSO are a=0.5713nm, b=0.5440nm and c=0.7890nm. [110]-orthorhombic oriented
DSO has a square lattice referred to as a “pseudo-cubic” crystal. For the LSMO/DSO sample, the
growth direction [110]-orthorhombic direction is c*-axis, [1 0]-orthorhombic direction is b*-axis
and [001]-orthorhombic direction is a*-axis. After transformation, the lattice constants of DSO
are a* =
= 0.3945nm, b* = c* =
= 0.3944nm, α = 2tan-1
= 92.80°, and β = γ = 90°.
Supplementary Fig. 1 shows the L-scan X-ray Diffraction patterns of the LSMO film grown
directly on DSO substrate. The DSO peaks (002) and (003) correspond to the out-of-plane lattice
constant c* = 3.944 Å. The satellite peaks located around the main LSMO peaks, which are
labeled by small arrows in Supplementary Fig. 1, arise from the thickness fringes. The beautiful
fringes indicate an extremely smooth surface and interface of the as-grown high crystallinity
LSMO film. From the oscillation peak positions, the film thickness of LSMO film dLSMO is
estimated to be 12.6nm.
The reciprocal space mappings around of (002)HL, (002)KL, ( 03)HL, and (013)KL for
LSMO/DSO are shown in Supplementary Fig. 2, which are measured in the X-ray
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Demonstration and Development (XDD) beamline at the Singapore Synchrotron Light Source
(SSLS). From Supplementary Fig. 2 (a) and (b), we can see that the peaks for LSMO film layer
are right below the DSO substrate peaks. It means that there is no tilt between the LSMO layer
and DSO substrate. The peaks around LSMO feature along L are arisen from the thickness
fringes which is the same as the satellite peaks shown in Supplementary Fig. 1. The streaks
around the DSO substrate in Supplementary Fig. 2 (a) and (b) are due to the diffraction system
and beamline. The spots from LSMO remain to be a single peak for all mappings, showing a
high quality of epitaxial growth of the thin-film layer.
To obtain the precise lattice constants, the reciprocal space vectors were measured. The
measured reciprocal space vectors for DSO substrate are (-0.0004 0.0000 2.0012), (-0.9995
0.0000 3.0018) and (0.0000 1.0000 3.0019). The measured reciprocal space vectors for DSO
substrate are then corrected to (002), ( 03) and (013). The measured reciprocal space vectors for
LSMO film (on DSO) are (0.0001 -0.0037 2.0604), (-0.9963 0.0000 3.0900) and (0.0000
0.9960 3.0924). After correction, we obtain the lattice constants of La0.7Sr0.3MnO3 film that are
monoclinic: a = 0.3955(3) nm, b = 0.3938(3) nm, c = 0.3831(1) nm, α = 92.79(8)°, and β = γ =
90°. The c/a is 0.968 and much smaller than 1. The LSMO/DSO system is under large tensile
strain.
The reciprocal space mappings around of (002)HL, (002)KL, ( 03)HL, and (013)KL for
LSMO/STO are shown in Supplementary Fig. 3. The mappings show a high quality of epitaxial
growth of the thin-film layer. The measured reciprocal space vectors for SrTiO3 (STO) substrate
are (0.0006 0.0014 3.0012), (-0.9995 0.0008 3.0007) and (-0.0012 1.0005 3.0026). The
measured RSVs for STO substrate are corrected to (003), ( 03) and (013). The measured RSVs
for LSMO film are (0.0001 0.0002 3.0370), (-0.9995 -0.0004 3.0365) and (-0.0016 0.9994
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3.0376). After corrected, we can obtain that the c/a is 0.995 and smaller than 1. The LSMO/STO
system is under tensile strain. The film thickness dLSMO (on STO) is estimated to be 11.2nm.
Spectroscopic Ellipsometry measurements
Ellipsometry is a non-destructive and precise optical analytical method that probes optical
properties from samples. This method is self-normalizing without performing a Kramers-Kronig
transformation.1-5 The raw data measured by ellipsometry is expressed in terms of Ψ (the
amplitude ratio between the p- and s-polarized light waves) and Δ (the phase difference between
the p- and s-polarized light waves), which are defined as3
tan  exp  i  
rp
rs
,
(1)
where rp and rs are the reflectivity of p- (parallel to the plane of incident) and s- (perpendicular to
the plane of incident) polarized light. From the Fresnel equations, these two quantities can be
defined as
rpij 
n j cos i  ni cos  j
(2)
n j cos i  ni cos  j
and
rsij 
ni cos i  n j cos  j
ni cos i  n j cos  j
.
(3)
Here, n and θ represent the refraction index and angle of incident from the surface normal,
respectively. The i and j represent the two materials involved in the photon propagation. From
here, the complex dielectric function ε(ω) = ε1(ω) + iε2(ω) can be obtained using
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     n   ,
(4)
where ω is the photon frequency.
In this paper, spectroscopic ellipsometry measurements are performed using a costumemade Variable Angle Spectroscopic Ellipsometer (VASE) of J. A. Woollam Co., Inc in the
photon energy range of 0.55 – 6 eV. The incident angle is 70º from the sample normal and the
incident light is 45º polarized. The measured Ψ and Δ spectra of the LSMO samples are shown in
Supplementary Fig. 5. For bulk DSO substrate, the incident angle dependent (65°, 70°, 75°)
measured Ψ and Δ spectra are shown in Supplementary Fig. 6. Noting that the temperaturedependent Ψ and Δ spectra are measured from 4K to 350K (not shown in figures). The spectra
show temperature independence, which suggests that the optical properties of bulk DSO are
temperature dependent in the measured range of temperature. The ε(ω) of bulk DSO substrate is
obtained from Ψ and Δ through direct function inversion of Supplementary Eqs. 1–4, as shown
in Supplementary Fig. 7.
To extract the ε(ω) of the LSMO films, the samples are modelled as having two layers:
LSMO film on DSO substrate. According to the analysis of wave propagation through stratified
media,1,6,7 the reflectivity (and thus Ψ and Δ via Supplementary Eq. 1) of LSMO film on DSO
substrate can be expressed as,
rmulti 
ramb,LSMO  rLSMO,DSOei 2 LSMO
1  ramb,LSMO rLSMO,DSOei 2 LSMO
,
(5)
where
 LSMO 
2 d LSMO

2
2
nLSMO
 namb
sin 2  .
(6)
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Here, the subscripts multi and amb represent the LSMO on DSO multilayer system and the
ambient, respectively, while δLSMO is the change in light phase as it travels through the LSMO
film, dLSMO is the thickness of the LSMO film, and λ is the light wavelength.
Since the ε(ω) of bulk DSO (Supplementary Fig. 6), dLSMO, and θ (70º) are known, the ε(ω)
of LSMO film is extracted from Ψ and Δ through fitting8 with Drude-Lorentz oscillators
according to
        k
0,2 k
 p ,k
.
  2  i k 
(7)
The high frequency dielectric constant is denoted by ε∞; ωp,k, ω0,k, and Γk are the plasma
frequency, the transverse frequency (eigen frequency), and the line width (scattering rate) of the
k-th oscillator, respectively. The extracted complex dielectric function ε(ω) of LSMO film from
4 K to 350 K are shown in Supplementary Figs. 8 (a) and (b). The low energy part (below 1.8eV)
of ε1 and ε2 shows significant variation with temperature while the high energy part remains
relatively unchanged. The contour plots of ε1 and ε2 as shown in Supplementary Figs. 8 (c) and
(d). The contour plot with color fill of Δσ1 (see in main text) as functions of temperature and
photon energy is shown in Supplementary Figs. 8 (e). The low energy region (below 1.8 eV)
shows a dramatic color (intensity) change at around 140 K as temperature decreases. In
Supplementary Figs. 8 (b), (d) and (e), the peak near 1.0 eV has been ascribed to eg - eg transition
with the parallel spin (Jahn-Teller effect).9,10 The intensity of this peak increases as temperature
decreases. While the position of this peak shifts to lower energy.
The optical conductivity is obtained from dielectric function ε(ω) using 1     0 2    ,
which is shown in main text.
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X-ray magnetic circular dichroism measurements
The angle-dependent X-ray magnetic circular dichroism (XMCD) sum rule11-13 states that
the ratio of the net spin and orbital moments ( mspin and morb ) are:

T
mspin  7m  nh  B

orb
m
  nh  B
2[AL3  2AL2 ]
, and
[ AL3  AL2 ]
4[AL3  AL2 ]
3[ AL3  AL2 ]
(8)
,
(9)
where AL3 and AL2 , AL3 and AL2 are the L3- and L2-edge integrated X-ray absorption spectra
(XAS) and XMCD intensities, respectively; nh=10 - n3d where n3d is the 3d electron occupation

number; mT is the angular-dependent magnetic dipole moment. According to the angle
averaging spin sum rule,13 the value of mT is equal to zero at the magic angle (θ=54.7°). Then
mspin can be approximately obtained in GI geometry (θ=60°) by applying the sum rule.11,12 Then,
for n3d=4.2914 and by taking into account the circular polarization degree, value of mspin , morb and
mtotal  mspin  morb as a function of temperature is shown in Supplementary Table 1 (The Mn
L3,2-edges XMCD and its energy integral for LSMO/DSO are shown in Supplementary Fig. 10).
It is noted that there is no XMCD observed at 300 K for LSMO/DSO.
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The study on La0.7Sr0.3MnO3 (LSMO) films on SrTiO3 (STO) substrates (LSMO/STO)
To further support the importance of temperature dependence of p-d hybridization, we use
temperature-dependent XAS, transport, and XMCD to investigate the mechanism governing the
transport and magnetic properties of La0.7Sr0.3MnO3 (LSMO) films on SrTiO3 (STO) substrates
(LSMO/STO). From HR-XRD measurements, we obtained that the lattice strain (c/a ratio) of
LSMO/STO is a small tensile strain (c/a=0.995) with 11.2 nm thickness (see discussion above).
Supplementary Figure 12a shows the O K-edge XAS of LSMO/STO for polarization Ec
(normal incidence) as functions of temperature. Interestingly, the Mn3d-O2p hybridization
strength increases when the system is cooling down to 80 K. Supplementary Figure 12b presents
integrated spectral weight
defined as
from 527 eV to 533.5 eV for O
K-edge spectra (Supplementary Fig. 12a) and from 636 eV to 649 eV for Mn L3-edge spectra
(Supplementary Fig. 13). The enhancement of spectral weight by about ~11% in the pre-edge
region (527-533.5 eV) of O K-edge XAS (black dots in Supplementary Fig. 12b) as temperature
decreases corresponds to an increase of O2p-Mn3d hybridization strength.15 In contrast, the
Mn3d occupancy (red squares in Supplementary Fig. 12b) is almost unchanged when
temperature decreases.
In-plane transport property of the LSMO/STO films is shown in Supplementary Fig. 12c. It
shows metallic behavior with slightly reduced metal-insulator transition (MIT) temperature
TMIT~330 K.16 The monotonic decrease of resistivity is consistent with the monotonic increase of
the p-d hybridization strength (
) as temperature decreases, which is also consistent with the
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opposite temperature-dependent trend observed in LSMO/DSO. We argue that the transport
properties of LSMO/STO can also be explained to be the consequence of the temperature
dependent p-d hybridization, similar to that we discussed for the case of LSMO/DSO in the main
text. Since
decreases
determines the bandwidths of the two Jahn-Teller-split eg bands, as temperature
increases (see black dots in Supplementary Fig. 12b), causing the bandwidth to
increase. This in turn increases the density of states at the Fermi level (DOS(EF)). Since
resistivity is inversely proportional to this quantity ((DOS(EF))), the resistivity decreases yielding
a metallic behavior.
We do the XMCD measurements on LSMO/STO at 80 K, 300 K, and 390 K. (the Mn L3,2
edges XAS of LSMO/STO with their corresponding XMCD signal (µ+ - µ-) at the bottom are
shown in Supplementary Fig. 14) The extracted total magnetic moments (mtotal) as functions of
temperature are shown in Supplementary Fig. 12d and Supplementary Table 2. Upon cooling,
the XMCD signal enhances as temperature decreases. We argue that the double-exchange
coupling (
), despite weaker compared to that in bulk LSMO, still dominates over the
superexchange coupling in LSMO/STO. As temperature decreases,
increases (see black dots
in Supplementary Fig. 12b). And then the double-exchange coupling increases, driving the
system more ferromagnetic (Supplementary Fig. 12d).
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