Tackling multiferroic YMnO 3 and BiFeO 3 in BM25
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kling multiferroic YMnO 3 and BiFeO 3 in BM25 APR-2012, http://usuaris.tinet.cat/~xmarti/talks X. Marti, V. Holy Charles University, Prague P. Ferrer, T. Schulli ESRF, Grenoble J. Herrero- Albillos BESSY, Berlin J. Narvaez, G. Catalan CIN2, Barcelona N. Barrett, CEA, Gif-sur-Yvette M. Alexe MPI, Halle [email protected] BiFeO 3 (AF, FE) = BULK SKIN http://usuaris.tinet.cat/~xmarti/
description
Tackling multiferroic YMnO 3 and BiFeO 3 in BM25 17-APR-2012, http:// usuaris.tinet.cat/~xmarti/talks. X. Marti, V. Holy Charles University, Prague P. Ferrer, T. Schulli ESRF, Grenoble J. Herrero-Albillos BESSY, Berlin J. Narvaez, G. Catalan CIN2, Barcelona N. Barrett, - PowerPoint PPT Presentation
Transcript of Tackling multiferroic YMnO 3 and BiFeO 3 in BM25
Tackling multiferroic YMnO3 and BiFeO3 in BM25 17-APR-2012, http://usuaris.tinet.cat/~xmarti/talks
X. Marti, V. HolyCharles University, Prague
P. Ferrer, T. SchulliESRF, Grenoble
J. Herrero-AlbillosBESSY, Berlin
J. Narvaez, G. CatalanCIN2, Barcelona
N. Barrett, CEA, Gif-sur-Yvette
M. AlexeMPI, Halle
BiFeO3(AF, FE) =
BULK
SKIN
http://usuaris.tinet.cat/~xmarti/talks
Tackling multiferroic YMnO3 and BiFeO3 in BM25 17-APR-2012, http://usuaris.tinet.cat/~xmarti/talks
X. Marti, V. HolyCharles University, Prague
P. Ferrer, T. SchulliESRF, Grenoble
J. Herrero-AlbillosBESSY, Berlin
J. Narvaez, G. CatalanCIN2, Barcelona
N. Barrett, CEA, Gif-sur-Yvette
M. AlexeMPI, Halle
Something
http://usuaris.tinet.cat/~xmarti/talks
BiFeO3(AF, FE) =
BULK
SKIN
Courtesy of G. Catalan
1. Small changes of the out-of-plane parameter
2. …and confined in a few (?) nm thick topmost surface
http://henke.lbl.gov/optical_constants/
BiFeO3
αi
Ei
),2/()Re(),Im(/1 zzzz QqaLq
.)1(2)(sin)1(2)(sin)),sin()(sin( 22 nnKqKQ fizfiz
αiEi
Two exit angles: αf , Ψ
Z: perpendicular to surface
(i.e. latitude, longitude)
Primary beam
Pseudocubic reciprocal space coordinates :
qx = K * [ cos(αf) * cos(Ψ) - cos(αI) ] ~ Hqy = K * [ cos(αf) * sin(Ψ) ] ~ Kqz = K * [ sin(αf) + sin(αI) ] ~ LK = 2*π/λ
X
Y
Correction for refraction
[email protected] http://usuaris.tinet.cat/~xmarti/talks
1. Small changes of the out-of-plane parameter
2. …and confined in a few (?) nm thick topmost surface
http://henke.lbl.gov/optical_constants/
1. Small changes of the out-of-plane parameter
2. …and confined in a few (?) nm thick topmost surface
To circumvent refraction we scanned both
energy and incidence angle
The inter-planar distances are a fingerprint of each material/phase/skin
Qx (Å-1)
Qz (Å
-1)
-0.1 0 0.1
0.4
0.45
0.5
0.4 0.45 0.50
5
10
Q (Å-1)
log(
Inte
nsity
)
Periodicites and directions Only periodicities
Pseudocubic reciprocal space coordinates :
qx = K * [ cos(αf) * cos(Ψ) - cos(αI) ] ~ Hqy = K * [ cos(αf) * sin(Ψ) ] ~ Kqz = K * [ sin(αf) + sin(αI) ] ~ LK = 2*π/λ
hklzyx dqqqQ 222
http://usuaris.tinet.cat/~xmarti/talks
There is a skin layer
Changing the energy(no refraction correction required)
BULK SKIN
Q(no alignment required)
THICKNESS < 40 nm
There is a skin layer
Changing the energy(no refraction correction required)
BULK SKIN
Q(no alignment required)
THICKNESS < 40 nm
splitting
shift
Measured CorrectedBULK SKIN
Q Q
Changing the energy(no refraction correction required)
There is a skin [email protected]
THICKNESS < 40 nm
Measured Corrected
Changing the angles
BULK SKIN
Changing the energy(no refraction correction required)
There is a skin [email protected]
THICKNESS < 40 nm
Temperature dependence (low temperature)
The skin has its own phase transitions
Ac anomalies seen in 3 samples by 3 different growers !!!
Independent of polishing process
X-ray diffraction Impedance
0 50 100 150 200 250 3000
20
40
60
80
100
0 50 100 150 200 250 3000.00
0.01
0.02
0.03
0.04
'(em
uOe-1
mol
-1)
T (K)
0 T 1 T
Cp (J
mol
-1 K
-1)
T (K)
Heat capacity and magnetic susceptibility
50 100 150 200 250 3001
1.005
1.01
1.015
Temperature (K)
Q/Q
300
K (Å
)
Bulk sensitiveSurface sensitive
YMnO3
I. Fina, F. Sanchez, J. Fontcuberta, ICMABJ. Ander Gallastegui, F. Jimenez Villacorta
Mn Mn
O
Mn Mn
O
-200 -100 0 100 200
12.9
13.1
13.3
E (kV/cm)
70 nm
r
140 nm
-200 -100 0 100 200
9.2
9.4
9.6
E (kV/cm)-200 -100 0 100 200
7.7
7.9
8.1 28 nm
E (kV/cm)
2.0 2.1K (r.l.u.)
2.0 2.1
7.9
8.0
L (r
.l.u.
)
H (r.l.u.) 2.0 2.1
7.9
8.0
H (r.l.u.)
L (r
.l.u.
)
2.0 2.1K (r.l.u.)
2.0 2.1
7.9
8.0
H (r.l.u.)
L (r
.l.u.
)
2.0 2.1K (r.l.u.)
More FE Less FE
YMnO3
I. Fina, F. Sanchez, J. Fontcuberta, ICMABJ. Ander Gallastegui, F. Jimenez Villacorta
Mn Mn
O
Mn Mn
O
More FE Less FE
YMnO3
I. Fina, F. Sanchez, J. Fontcuberta, ICMABJ. Ander Gallastegui, F. Jimenez Villacorta
EXAFS XRD
L S d
Bonding angleMagnetic properties
Ferroelectric properties
Strained YMnO3 thin films
Mn Mn
O
Mn Mn
O
49 nm
106 nm
EXAFS k3(k) Filtered k3(k) Fitting
(a)
k3 ·(k
) (Å
-2)
4 6 8 10 12
1.89 1.90 1.91 1.92
2.11
2.12
2.13
2.14
x
Long
bon
d (Å
)
Short bond (Å)
9.000
15.00
20.00
25.00
30.00
35.00(d)
49 nm1.89 1.90 1.91 1.92
2.13
2.14
2.15
2.16
Long
bon
d (Å
)
Short bond (Å)
9.000
15.00
20.00
25.00
30.00
35.00 (c)
106 nm
x
Mn-O d=1.90 Å Mn-O d=2.14 Å
Wavenumber (Å-1)
49 nm
FT Module Fitting
1 2 3
Mn-O d=1.90 Å Mn-O d=2.14 Å
106 nm
(b)
FT M
agni
tude
Distance (Å)
EXAFS
L S
S (Å)
L (Å
)
E-type, P || a
A-type, no P
106 nm
49 nm
1.85 1.9 1.952.1
2.12
2.14
2.16
2.18
2.2
2.22
135
140
145
150
155Bulk YMnO3
EpilayersYMnO3
EXAFS XRD
L S d
Bonding angleMagnetic properties
Ferroelectric properties
Mn Mn
O
Mn Mn
O
More FE Less FE
More FE
Less FE
[010]
[100]S
L
LS
L
S
SL
Mn Mn
O
D
L S
θ
[110]
[001]
(a)
(b)
[001]
[110]
(c)
LSE
49 nm
106 nm
EXAFS k3(k) Filtered k3(k) Fitting
(a)
k3 ·(k
) (Å
-2)
4 6 8 10 12
1.89 1.90 1.91 1.92
2.11
2.12
2.13
2.14
x
Long
bon
d (Å
)
Short bond (Å)
9.000
15.00
20.00
25.00
30.00
35.00(d)
49 nm1.89 1.90 1.91 1.92
2.13
2.14
2.15
2.16
Long
bon
d (Å
)
Short bond (Å)
9.000
15.00
20.00
25.00
30.00
35.00 (c)
106 nm
x
Mn-O d=1.90 Å Mn-O d=2.14 Å
Wavenumber (Å-1)
49 nm
FT Module Fitting
1 2 3
Mn-O d=1.90 Å Mn-O d=2.14 Å
106 nm
(b)
FT M
agni
tude
Distance (Å)
EXAFS XRD
L S d
Bonding angleMagnetic properties
Ferroelectric properties
Strained YMnO3 thin films BiFeO3 (AF, FE)
=BULK
SKIN
[010]
[100]S
L
LS
L
S
SL
Mn Mn
O
D
L Sθ
[110]
[001]
(a)
(b)
[001]
[110]
(c)
LSE
49 nm
106 nm
EXAFS k3(k) Filtered k3(k) Fitting
(a)
k3 ·(k)
(Å-2 )
4 6 8 10 12
1. 89 1.90 1.91 1. 92
2.11
2.12
2.13
2.14
x
Long
bon
d (Å
)
Short bond (Å)
9.000
15.00
20.00
25.00
30.00
35.00(d)
49 nm1.89 1.90 1.91 1.92
2. 13
2. 14
2. 15
2. 16
Long
bon
d (Å
)
Short bon d (Å)
9.000
15.00
20.00
25.00
30.00
35.00 (c)
106 nm
x
Mn-O d=1.90 Å Mn-O d=2.14 Å
Wavenumber (Å-1)
49 nm
FT Module Fit ting
1 2 3
M n-O d=1.90 Å M n-O d=2.14 Å
106 nm
(b)
FT M
agni
tude
Distance (Å)
EXAFS XRD
L S d
Bonding angleMagnetic properties
Ferroelectric properties
Strained YMnO3 thin films BiFeO3(AF, FE) =
BULK
SKIN
Tackling multiferroic YMnO3 and BiFeO3 in BM25 17-APR-2012, http://usuaris.tinet.cat/xmarti/talks
THANKS FOR YOUR ATTENTION !!
- EXAFS: - bonding angle in YMnO3 films increases with decreasing strain
- Grazing incidence: evidences a BiFeO3 skin layer.
