Comparing XRD data for 225C and 300C growth of Si-Heusler.
Some composition assumption for sample grown at 225C.
S230 grown at 300CSi Comp = 22.9 at.%
S239 grown at 225CSi Comp = 27.8 at.%
1009080706050Co Percent Metal
1.0
0.8
0.6
0.4
0.2
0.0
x10-2
4.10
4.05
4.00
3.95
3.90
0.12
0.10
0.08
0.06
0.04
0.02
0.00
1.003
1.002
1.001
1.000
0.999
0.998
0.997
In-Plane P
osition
4.0
3.5
3.0
2.5
2.0
1.5
1.0
In-Plane FW
HM
10-2
1.0
0.8
0.6
0.4
0.2
x10-3
2.06
2.04
2.02
2.00
1.98
1.96
1.94
5
4
3
2
1
0
x10-4
1.03
1.02
1.01
1.00
0.99
0.98
0.97
Integrated Intensity
Peak Position [rlu]
Peak FWHM [rlu]
L(014)h=(022)c K(014)h=(022)c L(102)h=(002)c L(011)h=(111)c
Int=0.0069
1009080706050Co Percent Metal
2.5
2.0
1.5
1.0
0.5
0.0
x10-2
4.10
4.05
4.00
3.95
3.90
0.12
0.10
0.08
0.06
0.04
0.02
0.00
1.003
1.002
1.001
1.000
0.999
0.998
0.997
In-Plane P
osition
4.0
3.5
3.0
2.5
2.0
1.5
1.0
In-Plane FW
HM
10-2
3.0
2.5
2.0
1.5
1.0
0.5
0.0
x10-3
2.06
2.04
2.02
2.00
1.98
1.96
1.94
1.5
1.0
0.5
0.0
x10-4
1.03
1.02
1.01
1.00
0.99
0.98
0.97
Integrated Intensity
Peak Position [rlu]
Peak FWHM [rlu]
L(014)h=(022)c K(014)h=(022)c L(102)h=(002)c L(011)h=(111)c
Things I noticed:• (022) intensity higher for 225C growth at Heusler Comp• Large area of higher intensity and in-plane lattice matching (65-
90)%Co– FWHM shows similar trend
• No Significant difference in in-plane peak width for the two growth temperatures
• (111) very wide at 225C growth• On the 300C sample, the strain is different for each reflection (the
position traces do not collapse on top of each other) wereas they agree in the 225C sample
• Comparing Zero Strain w/Si concentration suggests zero strain if Si was 25at%
• Zero Strain doesn’t necessarily correspond with highest intensity of narrowest peak
Comparing Chemical Order
3
4
567
0.01
2
3
4
567
0.1
2
3
4
Inte
nsity
Rat
io
1009080706050Co Percent Metal
S1/F (300C) S2/F S1/F (225C) S2/F
The idea here is to measure the chemical ordering qualitatively. I’ve divided the integrated intensity of each superlattice peak by the fundamental to remove variations in structural disorder.
F=(022)c=(014)hS1=(002)c=(102)hS2=(111)c=(011)h
•No significant changes in intensity within the “good” region (65-85)% Co•No difference in S1/F for the two temperatures•Significant difference in intensities for S2/F: the (111) peak is MUCH stronger relative to the fundamental peak for 300C growth
Comparing phi-scan FWHM• Voigt could not fit well, so I found
FWHM via max value and located max/2 in the data after background subraction
• S239 had 2 components probably due to 2 distinct populations of grain sizes. I fit the wider as a polynomial background
• Clearly, the sample grown at 225C has a narrower width at the Heusler composition
FWHM vs Comp at Two Growth Temps
Example of two components in s239 Heusler Stoichiometry Data Compare
2
3
4567
1
2
3
4
Phi
-Sca
n FW
HM
[Deg
]
1009080706050Co Percent Metal
s239 (225C) s230 (300C)
8
6
4
2
Nor
med
Inte
nsity
x 1
0-3
26.025.024.023.022.021.0Phi [Deg]
Data Fit Bkg
Voigt Fit: |X|² = 2.8973Intensity: 0.001946 ± 3.8349e-05Amplitude: 0.0059389 ± 6.5139e-05Position: 23.803 ± 0.00096075FWHM: 0.2086 ± 0.0034152Shape: 10000 ± 0
0.3
0.2
0.1
0.0
Nor
med
Inte
nsity
26.025.024.023.022.021.0Phi [Deg]
s239 (225C) s230 (300C)
L-scans of (014) on s231 (Si~19at%)Grown at 150C and 1/3 as Thick as Others
• A couple bad spots at ~90% Co• Zero strain @ ~84% Co• Position/Strain changes monotonically/linearly• Width strange
4.08
4.06
4.04
4.02
4.00
3.98
3.96
3.94
Pos
ition
[rlu
]
1009080706050Co Percent Metal
60
55
50
45
40
35
FWH
M [rlu 10
-3]
6810-4
2
4
6810-3
2
4
68
Integrated Intensity
Some General Conclusions• Si-concentration is a bigger factor to determine strain than Co/Mn
ratio• Higher Co concentration is better ordered than Heusler
stoichiometry regardless of growth temp according to intensities• Large region of composition gives good ordering according to peak
widths• These samples are still too different to make a definitive statement
on growth temperature– Different Si concentrations– Different layer ordering when grown– Different thicknesses (at least the 150C sample)
• Improving the study:– Study Si-dependant samples– Grow all three samples in a immediately after each other rather than
venting or composition recalibration to ensure const Si btwn samples
S241: Ternary Sample Grown at 225C
43
21
0X
Pos
[mm
]
6420 Y Pos [mm]
20
15
10
5
0
L Intensity 10-3
43
21
0X
Pos
[mm
]
6420 Y Pos [mm]
1086420
K Intensity 10
-3
43
21
0X
Pos
[mm
]
6420 Y Pos [mm]
4
4
3.97 3.96
4.024.003.983.963.94
L Position
43
21
0X
Pos
[mm
]
6420 Y Pos [mm]
1.000
0.998
0.996
K P
osition
43
21
0X
Pos
[mm
]
6420 Y Pos [mm]
807060504030
L FWH
M 10
-3
43
21
0X
Pos
[mm
]
6420 Y Pos [mm]
3530252015
K FW
HM
10-3
43
21
0X
Pos
[mm
]
6420 Y Pos [mm]
0.50.40.30.20.10.0
L Shape
43
21
0X
Pos
[mm
]
6420 Y Pos [mm]
0.50.40.30.20.10.0
K S
hape
• L and K scans of the (014) reflection
• Phi scans are difficult to fit – just calc FWHM from data
• Data taken at corner of ternary sample nearest Co Apex
• Along Diagonal boundary, Co~80% of metal concentration
• Along base, Si~10%
In-Plane Out-of-Plane4
32
10
X P
os [m
m]
6420 Y Pos [mm]
1.0
0.8
0.6
0.4
0.2FW
HM
[Deg]
Phi-scan FWHM
Ternary General Conclusions
• Brightest peaks correspond with narrowest width which occurs at the edge of the region corresponding to Co 80% (out of metal concentration). This is the spot of best crystal structure
• Best crystal structure DOES NOT correspond to zero strain, OR Heusler Stoichiometry
• Don’t know Si concentration yet
XRF Analysis of s238,38,41
Used to tweak first slide’s results and to correlate structural data
XRF analysis on binary samples: s238(150C), s239(225C)
• Compared XRF thicknesses w/ AA monitor – Quartz crystal expected thickness during growth– Both samples came to significantly
lower thicknesses– Since reduction ~ same for each
element, composition was not effected significantly
– This is NOT effected by Duke profilometer readings, since both are calibrated to the same calibration sample and same measured sample thickness
• Fluctuation seems fairly large for Si and Co between the two samples. Mn held steady.
900
800
700
600
500
400
300
200
Thic
knes
s [Å
]
-6 -4 -2 0 2 4 6Sample Position [mm]
Film ThicknessSi-Heusler Number Density
s239 s238Expected: 700Å, 687Å
800
600
400
200
0
Thic
knes
s [Å
]
-6 -4 -2 0 2 4 6Sample Position [mm]
s239 Component ThicknessesAssuming Si-Heusler Number Density
Co Mn Si TotalCmpr to Calc: (81%, 88%, 85%, 84%)
800
600
400
200
0
Thic
knes
s [Å
]
-6 -4 -2 0 2 4 6Sample Position [mm]
s238 Component ThicknessesAssuming Si-Heusler Number Density
Co Mn Si TotalCmpr to Calc: (85%, 88%, 81%, 79%)
Mn pos way off again!
Binary Compositions• Despite fluctuations, the
offset of the Mn in s238 seems to have compensated and produced similar Si-concentrations
• Although Si is higher as expected, Co/Mn=2 pos changed and gives near zero strain (see slide 1)
• NOTE: we have no structural data (RHEED or XRD) on s238.
100
80
60
40
20
0
Com
posi
tion
[at.%
]
-6 -4 -2 0 2 4Sample Position [mm]
0.1
2
4
681
2
4
6810
Metal R
atio
s239 Si Heusler CoPercent MnPercent SiPercent MetalRatio
Co/Mn=2@ x=-0.4
Si=27.8 at.%
100
80
60
40
20
0
Com
posi
tion
[at.%
]
-6 -4 -2 0 2 4 6Sample Position [mm]
0.1
2
4
681
2
4
6810
Metal R
atio
s238 Si Heusler CoPercent MnPercent SiPercent MetalRatio
Co/Mn=2@ x=0.1
Si=27.9 at.%
XRF analysis on Ternary• Composition values obtained and
used to correlate structural results between samples.
• Quantitative thickness comparisons detailed in table at bottom right.
• Total thickness comparison for s241 is better, giving 95% the expected value.
• Co is nominally the same low value seen in other samples
• Mn thickness matches expected here, giving large fluctuation from binary samples
• Si thickness measurement was very low even though Liang had tried to increase the Si amount
64
20
-2-4
Y P
os [m
m]
-6 -4 -2 0 2 4 6X Pos [mm]
Si
Mn
Co
15
20
25
30
35
40
45
50
3035
4045
5055
6065
70
15
20
2530
35
4045
50
55
Film CompositionAtomic Percent
64
20
-2-4
Y P
os [m
m]
6420-2-4-6X Pos [mm]
400 390
380
380
370 370
370
360
360
360 350
350
350
370
360
350
390
380
370
360
350
Total Thickness [Å]
Total Thick Calc: 390Å; (95%)Co Max: 262Å; Calc: 307Å (85%)
Min: 100Å; Calc: 115Å (87%)MnMax: 223Å; Calc: 225Å (97%)
Min: 39Å; Calc: 39Å (100%)Si Max: 206Å; Calc: 261Å (79%)
Min: 40Å; Calc: 44Å (91%)
Curiosity: Co Zero Line Misalignment
• Co Zero line seen here and in previous Si-Heusler Ternary is not at 60 degrees.
• The Equal percentage lines (prev. slide) are not parallel with this line and are actually closer to 60 degrees
• While equal percentage lines could be off due to experimental/analytical errors, the boundary can not
8
6
4
2
0
Y P
os [m
m]
86420X Pos [mm]
Sample Boundaries Equalateral Triangle
Si
Mn
Co
Co Zero Line
Possible causes of discrepancy of thicknesses from expected
• Liang says this AA lamps were at the end of their lifetime (each of them) and could cause a systematic error in deposition– Could they cause reduction AND fluctuation?
• Another possibility is the Quartz crystal may have been positioned improperly– would explain a systematic reduction in deposition, but good Mn
agreement on s241 counts against this possibility
• XRF fitting is still very much a black box– I tried fitting the data with different conditions but could find no
conditions that would improve the values– Stefan says as long as fitting procedure same for Standard and Sample,
fitting should be robust
Correlating Results (s230, s239, s241)
• Used XRF data to correlate Binary to Ternary sample
– Right: Blue trace=s239 & Green trace=s230
– Green dot is Si-Heusler
• Expected:– Pleateau of width and zero
in-plane strain in large compositional region, including Heusler
– Brightest spot & narrowest width (best ordering) not at Heusler Stoichiometry
– Best ordering at high Co
• Not Expected:– Heusler sees ~1/4% strain?– 25% Si does not intersect
w/best ordering?4
32
10
Y P
os [m
m]
6420 X Pos [mm]
80
70
60
50
40
30
L FWH
M [rlu] 10
-3
43
21
0Y
Pos
[mm
]
6420 X Pos [mm]
35
30
25
20
15
K FW
HM
[rlu] 10-3
43
21
0Y
Pos
[mm
]
6420 X Pos [mm]
1
0.9995
0.9
99
0.999
0.9
985
1.001
1.000
0.999
0.998
0.997
0.996
0.995
K-P
osition [rlu]4
32
10
Y P
os [m
m]
6420 X Pos [mm]
4.02 4.01
4
3.99 3.98
3.97 3.96
3.95
3.94
4.02
4.00
3.98
3.96
3.94
L-Position [rlu]
43
21
0Y
Pos
[mm
]
6420 X Pos [mm]
10
8
6
4
2
0
Integrated Intensity 10-3
43
21
0Y
Pos
[mm
]
6420 X Pos [mm]
2 1.5
1
0.5
0.3
0.2
2.0
1.5
1.0
0.5
Phi FW
HM
[Deg]
• Interpolated s241missing data assuming planar geometry
S239 (Binary) -> s241 (Ternary)• Ternary data sampled at
Binary compositions to compare XRD results
• Intensity traces remarkably similar (factor of ~½ comes from thickness difference)
• L-Positions identical• In-Plane positions have
strange discrepancies below 70% Co, otherwise agree
• In general, width in ternary larger than in binary
– Wider Out-of-Plane due to thickness difference but not much
– Why is Ternary In-Plane wider?
• Phi-direction continues the trend with larger width
• Both grown at 225C• Binary 590A; Ternary 370A• Layers: Binary = CoMnCoSi…
Ternary = CoMnSi…
2
3
456
1
2
3
45
Phi
FW
HM
[Deg
]
1009080706050Co Pecent Metal
Phi FWHM s239 s241
0.12
0.10
0.08
0.06
0.04
0.02
Out
-of-P
lane
[rlu
]
1009080706050Co Pecent Metal
40
35
30
25
20
15
10
In-Plane [rlu] 10
-3
L-FWHM s239 s241K-FWHM s239 s241
4.04
4.02
4.00
3.98
3.96
Out
-of-P
lane
[rlu
]
1009080706050Co Pecent Metal
1.002
1.001
1.000
0.999
0.998
In-Plane [rlu]
L-Position s239 s241K-Position s239 s241
4
10-4
2
4
10-3
2
4
10-2
2
Inte
grat
ed In
tens
ity
1009080706050Co Pecent Metal
Intensity s239 s241
S230 (Binary) -> s241 (Ternary)• Intensity traces again similar
This time the Binary is weaker• Intensity peak at ~68% in both
data sets (shows up more if linear scale)
• L-Positions again identical• In-Plane positions agree well
with slight offset from 1 in the ternary (probably diffractometer calibration)
• In general, width in ternary larger than in binary
– Wider Out-of-Plane due to thickness difference but not much
– Why is In-Plane wider?
• Phi-direction continues the trend with larger width. Slightly more discrepancy
2
3
456
1
2
3
45
Phi
FW
HM
[Deg
]
1009080706050Co Percent Metal
Phi FWHM s230 s241
0.12
0.10
0.08
0.06
0.04
0.02
Out
-of-P
lane
[rlu
]
1009080706050Co Percent Metal
40
35
30
25
20
15
10
In-Plane [rlu] 10
-3
L-FWHM s230 s241K-FWHM s230 s241
4.04
4.02
4.00
3.98
3.96
Out
-of-P
lane
[rlu
]
1009080706050Co Percent Metal
1.002
1.001
1.000
0.999
0.998
In-Plane [rlu]
L-Poistion s230 s241K-Position s230 s241
4
10-4
2
4
10-3
2
4
10-2
2
Inte
grat
ed in
tens
ity
1009080706050Co Percent Metal
Intensity s230 s241
• Binary grown at 300C; Ternary 225C• Binary 540A; Ternary 370A• Layers: Binary = CoMnCoSi…
Ternary = CoMnSi…
New General Conclusions
• I would say this shows good reproduction of data and gives us an idea of our error
• There could be a systematic error in composition causing the strain measurements to be off from the Heusler (1% is too far off to be from miscalibration of diffractometer) or there could be some Mn loss into the Ge substrate causing the Heusler comp to shift
Composition Grid
Integrated Intensity Strain
• Extracted contour data from XRF image
• Rotated contour data via MatrixLLS routine
• Fit each contour to quadratic• Displayed Fits as contours
Si15K0=0.44555 ± 0.00648K1=0.040633 ± 0.00339K2=-0.0022813 ± 0.000374
Si20K0=1.2363 ± 0.0105K1=0.046313 ± 0.00514K2=-0.0021496 ± 0.000545
Si25K0=2.0616 ± 0.0189K1=0.04832 ± 0.00965K2=-0.0018501 ± 0.00109
Si30K0=2.7888 ± 0.0296K1=0.090193 ± 0.0148K2=-0.0052631 ± 0.00168
Mn15K0=-0.8236 ± 0.0613K1=1.7841 ± 0.0531K2=0.0083783 ± 0.0101
Mn20K0=-2.4035 ± 0.114K1=1.7998 ± 0.0782K2=0.004038 ± 0.0124
Mn25K0=-3.668 ± 0.221K1=1.6548 ± 0.121K2=0.019848 ± 0.0157
Mn30K0=-4.6719 ± 0.355K1=1.5059 ± 0.164K2=0.025659 ± 0.0184
Mn35K0=-6.2028 ± 0.572K1=1.5223 ± 0.224K2=0.021491 ± 0.0217
Mn40K0=-8.8445 ± 1.51K1=1.9773 ± 0.52K2=-0.024579 ± 0.0443
Co70K0=2.5083 ± 0.55K1=-3.4524 ± 1.62K2=0.90463 ± 1.14
Co65K0=3.2558 ± 0.624K1=-1.3718 ± 0.965K2=-0.24273 ± 0.362
Co60K0=5.5251 ± 0.563K1=-2.1066 ± 0.573K2=0.028696 ± 0.142
Co55K0=8.7435 ± 0.56K1=-3.1711 ± 0.425K2=0.20905 ± 0.0787
Co50K0=9.3355 ± 0.377K1=-2.2143 ± 0.232K2=0.025914 ± 0.0347
Co45K0=11.633 ± 0.433K1=-2.4596 ± 0.218K2=0.059137 ± 0.0267
Co40K0=13.394 ± 0.337K1=-2.4422 ± 0.142K2=0.05703 ± 0.0146
Elasticity Formalism• Stress-strain relation relates 1x6 vectors via a 6x6 tensor:
– where σ is the stress, ε is the strain, and Cij represent the elastic moduli for the material
– Represents 6 equations relating 3 compressive and 3 tortional components
• With cubic symmetry, only three independent elastic moduli:– C11, C12, and C44
• Distributed symmetrically IF coordinate axes along (100)– only the C11 and C12 are needed to relate the x and z components
• With (111) epitaxial growth, C must be rotated– C actually a 4th rank tensor so rotation equation is
where derivatives are direction cosines
C
mnopp
l
o
k
n
j
m
iijkl C
xx
xx
xx
xxC
'''''
Rotating Elastic Moduli(001) Growth
44
44
44
111212
121112
121211
000000000000000000000000
cc
cccccccccc
Cij
(111) Growth
6614
1444
441414
331313
14131112
14131211
''0000''000000'0''000'''00''''00''''
'
cccc
cccccc
cccccccc
C ij
3
22' 44121113
cccc
3
42' 44121133
cccc
• Epitaxial films: σ3=0
• Cubic films: σ1=σ2 & ε1=ε2
• Only need third equation:• Solving for Lfilm
xxz A
cccccc
cc
441211
4412111
33
133 42
222''2
film
filmOutPlanez L
LL
film
filmInPlanex L
LL
1
A
LALL InPlaneOutPlanefilm
Known Elastic ModuliSubstance C11 C12 C44 A
Cu 1.68 1.21 0.75 0.73239
Ag 1.24 0.93 0.46 0.88259
Au 1.86 1.57 0.42 1.24551
Al 1.07 0.61 0.28 1.01466
Ge 1.29 0.48 0.67 0.36917
Si 1.66 0.64 0.80 0.43648
V 2.29 1.19 0.43 1.19249
Fe 2.34 1.36 1.18 0.55215
Ni 2.45 1.40 1.25 0.53659
Chose Fe since it’s a transition metal between Mn and Co
Doing the conversion…Out-of-Plane Strain In-Plane Strain
Lattice Parameter Mismatch
151050
-5
x10-3
(LOP-LGe)/LGe (LIP-LGe)/LGe
4
2
0
x10-3
Value of Plane ~ 2x10-4
151050
x10-3
Mismatch =(Lfilm-LGe)/LGe
5.76
5.72
5.68
5.64
5.658ÅFilmLattice Parameter [Å]
Points of Interest
• Literature Bulk Value = 5.654Å (-0.07% Mismatch)
• Brightest Spot on Ternary Sample– Composition ~ (64.0%Co, 12.5%Mn, 23.5%Si )– Lattice = 5.639Å (-0.34% Mismatch)
• Heusler Stoichiometry– Lattice = 5.670Å (+0.21% Mismatch)
Fitting LP to Plane• Plotted 0.005Å Contour• Variation ~±0.004Å
Obvious Curvature to LP 5.72 5.71
5.7
5.69
5.68
5.67
5.66
5.65
5.64
5.63
5.765.725.685.64
5.658ÅFilm Lattice Parameter [Å] Plane Fit Values ± Stdev
K0=5.6668 ± 0.000372K1=0.014838 ± 0.000107K2=-0.022755 ± 0.000207
0.0
14
0.012 0.01
0.01 0.008 0.006
0.004
0.002
0.002 0
0
-0.0
02
-0.0
04
0.005
-10
-5
0
5
10 Plane Fit R
esidual 10-3
Fitting LP=K0x+K1y+K2x2+K3xy+K4y2
• Plotted 0.002Å Contour• Variation ~±0.001Å
Residuals Very Flat
0.007 0.005
0.0
03
0.002
0.0
01
0
0
0
0
0
0
10
8
6
4
2
0
-2
Quad R
esidual [Å]10
-3
5.7
5.69 5.68 5.67
5.66
5.76
5.72
5.68
5.64
5.658ÅFilm Lattice Parameter [Å]
Quad Fit Values ± StdevK0=5.6623 ± 0.000368K1=0.019785 ± 0.000242K2=-0.024025 ± 0.000465K3=-0.00092084 ± 4.63e-005K4=-4.6692e-005 ± 8.47e-005K5=0.00045462 ± 0.000176
S230 Binary w/ Si=22.9 at.%• Closest Heusler Stoichiometry
– 5.674Å (+0.28%)
• Max Fundamental Intensity– 84.1% Co/Metal– (64.8% Co, 12.3% Mn, 22.9% Si)– 5.640Å (-0.32%)– Reproduces Ternary Sample
• Max (111) Intensity– 77.4% Co/Metal– (59.7% Co, 17.4% Mn, 22.9% Si)– 5.654Å (-0.07%)– Identical Lattice parameter with
bulk!
Linear RangeCo Percent Metal = 52.7% to 96.0%
Mismatch = 0.81% to -0.99%
5.70
5.68
5.66
5.64
5.62
Latti
ce P
aram
eter
[Å]
1009080706050
Co Percent Metal
-10
-5
0
5
10
Mism
atch 10-3
s230 (Si=22.9 at.%) Lattice Param From s241
Heusler Stoichiometry Bulk Lattice Constant Highest (022) Intensity Highest (111) Intensity
S239 Binary w/ Si=27.8 at.%• Closest Heusler Stoichiometry
– 5.659Å (+0.02%)
• Max Intensities (all three)– 80.6% Co/Metal– (58.2% Co, 14.0% Mn, 27.8% Si)– 5.636Å (-0.39%)
• Bulk Lattice Constant– 69.8% Co/Metal– (50.4% Co, 21.8% Mn, 27.8% Si)
• Linear Range not as well defined
Linear RangeCo Percent Metal ~ 58% to 87%
Mismatch ~ 0.34% to -0.53%
5.70
5.68
5.66
5.64
5.62
Latti
ce M
ism
atch
[Å]
1009080706050
Co Percent Metal
-10
-5
0
5
10
Mism
atch 10-3
s239 (Si=27.8 at. %) Lattice Param From s241
Heusler Stoichiometry Bulk Lattice Constant Highest Intensities
S239 Crystal Coherence via CTR• Good Fringes, but not w/out
doubling seen in other samples• (015) fringes very low, showing
low twinning• Film/Twinned Thickness = 2.5
10-5
10-4
10-3
10-2
10-1
Nor
mal
ized
Inte
nsity
4.24.14.03.93.8
L-Position [rlu]
s239 CTR Scans Pos_n0p5 (Lattice Match) Pos_n1p0 Pos_n2p0_01 (Brightest Spot) Pos_n2p0_02 (Narrower Slits)
Fringes dL~0.020
10-4
10-3
10-2
10-1
100
101
Nor
mal
ized
Inte
nsity
5.045.004.964.924.88
L - Position [rlu]
(015) CTRPos=-0.5
dL~0.050rlu
S239 Double Phase• No double peak found• Range is small so could miss it• More intensity on low-L side could
mean double peak• S241 pretty much the same• Look VERY different from s241
(see slide 35 for comparison)
(014) L-scan Before K-Correction
43
21
0Y
Pos
[mm
]
6420 X Pos [mm]
10
8
6
4
2
0
Integrated Intensity 10-3
6
5
4
3
2
1
Inte
nsity
x 1
0-3
4.084.044.003.963.92L Position [RLU]
s239 L014line1_8_48 L014line1_8_49 L014line1_8_50
s241
Lmesh_16_10
Checking s216 for Information
• Ternary• Growth Temp 300C (same as s230)• Thickness?• Took Fundamental L & K• S1 L, S2L, CTR at a few spots, Long Rods at a
few spots
Long 01 Rod ScansHot-Spot & Heusler Stoich
Double Phase Dark Strip
64
20
Dis
tanc
e [m
m]
86420 Distance [mm]
543210
x10-3
Intensity 0
Points where long rod scan was taken
10-6
10-5
10-4
10-3
10-2
10-1
Nor
mal
ized
Inte
nsity
654321 L
Pt14 (data03: S#1035)
10-6
10-5
10-4
10-3
10-2
10-1
Nor
mal
ized
Inte
nsity
654321 L
Pt03 (data03: S#1024)
10-6
10-5
10-4
10-3
10-2
10-1
Nor
mal
ized
Inte
nsity
654321 L
Heusler Stoich Hot Spot
Film orSubstrateTwinning?
CoMn
Si
10-5
10-4
10-3
10-2
Nor
mal
ized
Inte
nsity
2.42.22.01.81.6 L
Heusler Stoich Hot Spot Dark Strip Max Co Hot Strip Low Si
Substrate vs Film Twinning
• Can determine from width and position of (012) peak• Heusler is definitely film (wide and off of 2.0)• Hot Spot probably film (wide but on 2.0)• Others from substrate (all narrow and on 2.0)
– Note even lower on the ‘Hot Strip’, no film twinning
(01L) Peak
4.1
4.0
3.9
3.8
3.7
3.6
L P
ositi
on [r
lu]
54 52 50 48 46 44 42Co Composition [at.%]
-5.0-4.0
-3.0-2.0
Log Intensity
Muli-phase Behavior• Hex Phase monotonically
diverges from cubic lattice• Usually merges: stripe may be
interfering with transition• Sucks intensity from cube• Cube position seems constant
Si 15 at.%4.1
4.0
3.9
3.8
3.7
3.6
L P
ositi
on [r
lu]
52 50 48 46 44 42 40Co Composition [at.%]
-5.0-4.0
-3.0-2.0
Log Intensity
Si 20 at.%
stripe
stripe
8
6
4
2
Inte
nsity
x 1
0-4
4.104.003.903.803.703.60L Position [RLU]
Voigt Fit: |X|² = 1.3704Peak 0Amp: 0.00056056 ± 8.4816e-05Int: 3.7804e-05 ± 8.1694e-06Pos: 3.9837 ± 0.0014313FWHM: 0.063334 ± 0.0049043Shape: 0.00061552 ± 0.34225Peak 1Amp: 0.00027178 ± 4.1935e-05Int: 6.3633e-05 ± 1.8987e-05Pos: 3.877 ± 0.021477FWHM: 0.20753 ± 0.031239Shape: 0.1196 ± 0.95628
L014mesh_y_17_12 L014m_2voigt_FIT_17_12
Similar Compto Pt on Slide 31
Phase Boundaries
• The cubic phase boundary is just the low-limit of the intensity
• The Double Phase boundary was hand chosen by looking at each data set– 5-10% of the intensity by eye
was the low limit of the second phase
– Next block would be <1%
s216
Si 20%
Si 25%
Si 30%
Mn
50%C
o 65%C
o 60% Mn
45%
Converting to s241: Boundary Comparison• No indication s241 has double phase• No obvious correlation with double phase
boundary• S241 seems to have epitaxial growth in
larger composition region based on intensity
• Phi FWHM has good correlation with s216 boundary
Phi FWHM3.0
2.0
1.0
FWH
M [D
eg]
Lattice Parameter5.76
5.72
5.68
5.64
Log Intensity
-5.0
-4.0
-3.0
-2.0
Film Coherence from Peak FWHM
• Many things effect peak FWHM:– Particle size/coherent domains– Instrumental resolution– Antisite disorder on superlattice peaks– Strain fields
• Scherrer Equation gives particle size for powder diffraction up to 1000A