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