The X-Ray SEF - Massachusetts Institute of Technology
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The X-Ray SEF
Scott Speakman
13-4009A
x3-6887
[email protected]
http://prism.mit.edu/xray
This molecule is essential to life…
http://prism.mit.edu/xray
Intensity (a.u.)
The crystal structure of caffeine
was solved using X-ray diffraction
10
15
20
25
30
2q (deg.)
D. June Sutor, Acta Cryst. 11 (1958) 453
http://prism.mit.edu/xray
Caffeine is a crystal because its molecule
repeats in an orderly manner to fill space
http://prism.mit.edu/xray
X-Ray Diffraction is used to study
crystalline materials
X-rays scatter off of the
atoms in a sample
If those atoms are
systematically ordered, the
scattered X-rays tell us:
what atoms are present
how they are arranged
http://prism.mit.edu/xray
The XRD pattern of every crystalline
material is as distinct as your fingerprint
Intensity (a.u.)
Anhydrous Caffeine C8H10N4O2
Caffeine Hydrate C8H10N4O2H2O
10
15
20
25
30
2q (deg.)
http://prism.mit.edu/xray
Basic Diffractometer Operation
X-ray
tube
q
q
2q
Intensity (a.u.)
Detector
10
15
20
25
2 q (deg.)
30
A detector rotates around the sample, measuring
intensity as a function of the diffraction angle 2theta
XRD uses information about the position, intensity, width,
and shape of diffraction peaks in a pattern from a
polycrystalline sample.
http://prism.mit.edu/xray
The X-ray SEF has
Rigaku High-Speed Powder Diffractometer
PANalytical X’Pert Pro Multipurpose
Diffractometer
Bruker D8 Diffractometer with 2D Detector
Bruker D8 High-Resolution Thin-Film
Diffractometer
PANalytical Back-Reflection Laue Single
Crystal Diffractometer
Bruker Apex Single Crystal Diffractometer
Bruker Small Angle X-ray Scattering
Instrument
http://prism.mit.edu/xray
Sample Requirements
The Ideal Sample
Sample Size
Powder: 90 to 482 mm3
minimum 1.6 mm3
Solid: 10mm x 10mm
min: 1mm x 1mm
max: 55mm x 25mm
1” to 6” wafer
Characteristics
flat
grain size <10 mm
smooth
densely packed
infinitely thick (>0.3mm)
Real Samples
Multilayers:
Co(10nm)/Fe(15nm)/MgO(
2nm)/Si
42 alternating layers of
GaAs(104nm) and
Al0.941Ga0.059As(127nm)
Powder
3 specks of blue paint
0.05mm thick coating of
air-sensitive battery
materials
brake rotor
particles in suspension
http://prism.mit.edu/xray
Analyses Done Routinely
in the X-ray SEF
Discussed Today
Phase Identification
Crystallite Size Estimation
Lattice Parameter Refinement
Residual Stress Analysis
Evaluate Thin Film Quality
Reflectivity for Multilayer Thin
Film Analysis
Small Angle Diffraction of
Nano- and Meso- structures
Microdiffraction
Texture Analysis
In-situ Diffraction
Other Techniques
Index and Solve Crystal
Structures
Percent Crystallinity
Thin Film Analysis
Reciprocal Space Mapping
Relaxation & Strain
Defect Density
Single Crystal Diffraction
Crystal Orientation
Twinning & Other Defects
Small Angle X-ray Scattering
order/disorder of polymers
microstructure and porosity
amorphous texture
http://prism.mit.edu/xray
Phase Identification and Quantification
What phases, and how much of each, are present in this mixture of pigments?
21 wt%
Anatase, TiO2
Red Paint Pigment Mixture
Intensity (a.u.)
28 wt%
Hematite, Fe2O3
51 wt% Rutile, TiO2
25
30
35
40
2q (deg.)
http://prism.mit.edu/xray
Crystallite Size Analysis
Are any of the phases nanocrystalline; if so, what is their average crystallite size?
Red Paint Pigment Mixture
Intensity (a.u.)
Rutile: XS> 100 nm
Anatase: XS= 25 nm
Hematite: XS> 100 nm
22
23
24
25
26
27
28
29
2q (deg.)
http://prism.mit.edu/xray
Lattice Parameter Refinement
La2Zr2O7 undoped
4% Y-doping
8% Y-doping
10.821
4.0E-04
3.5E-04
10.818
3.0E-04
2.5E-04
10.815
2.0E-04
1.5E-04
10.812
Conductivity (S/cm)
Lattice Parameter (A)
Intensity (a.u.)
How does doping change the lattice parameter of this fuel cell electrolyte?
1.0E-04
10.809
5.0E-05
0
5
10
mol% Y
28.0
28.5
29.0
29.5
2q (deg.)
http://prism.mit.edu/xray
in situ XRD
we can perform these analyses, and many more, as a
function of:
temperature
cryostat: 11 K to RT
Powder Furnace: RT to 1200 C
Plate Furnace: RT to 900 C
environment
air
vacuum
inert gas
mildly reactive gas
time
time resolution as fast as 10 sec
more typical is 5+ min time resolution
http://prism.mit.edu/xray
in situ XRD of lattice parameters
How does the lattice parameter of LSO change with temperature?
1.5
c axis
1.3
1.1
b axis
0.7
0.5
0.3
a axis
delta L/Lo (%)
Intensity (a.u.)
0.9
0.1
-0.1
angle b
21
22
23
24
25
2q (deg.)
26
27
28 0
-0.3
-0.5
200
400
600
800
1000
1200
1400
1600
Temp (C)
http://prism.mit.edu/xray
in situ XRD of phase composition
How does the phase composition of this hydrogen
storage material change with time at 150°C?
NaH
Na3AlH6
NaAlH4
Al
N NaAlH4 N
k1t
0
NaAlH4
e
Phase Quantity (wt %)
80
60
40
20
N Na3 AlH6
1 0
k1 k1t
e
N
ek 2t N 0
ek 2t
Na3 AlH6
3 NaAlH4 k 2 k1
0
0
10000
20000
30000
40000
50000
60000
70000
Elapsed T ime (sec)
http://prism.mit.edu/xray
80000
Residual Stress Analysis
How do stresses in a Pd film change with H2 and temperature?
60
Pd in H2
Pd in He
Stress (MPa)
40
Intensity (a.u.)
XRD at 50°C
20
39.4 39.5 39.6 39.7 39.8 39.9 40.0 40.1 40.2 40.3 40.4 40.5 40.6 40.7
2q (deg.)
0
H2
-20
Pd
-40
Hastelloy
-60
0
100
200
300
400
500
600
Temp (°C)
http://prism.mit.edu/xray
Texture Pole Figures
How are the grains oriented in this refractory alloy for a satellite power system?
Distribution of <100> and <111>
directions in rolled Nb-1Zr
Rolled to 20% Reduction in Thickness
(less deformed)
Rolled 95% Reduction in Thickness
(more deformed)
http://prism.mit.edu/xray
Thin Film Rocking Curve
What is the quality of epitaxial semiconductor thin films
compared to the perfect single crystal substrate?
Poor Epitaxial Thin Film
Good Epitaxial Thin Film
Intensity (a.u.)
Perfect Single Crystal Substrate
Horrible Quality, Not Epitaxial
At All, Thin Film
30.6
30.7
30.8
30.9
31.0
31.1
31.2
31.3
31.4
2 q (deg.)
http://prism.mit.edu/xray
Thin Film Reflectivity
What is the arrangement and surface characteristics of a thin film of
GaAs on a Si substrate?
Thickness Roughness Density
(nm)
(nm)
(g/cm3)
C
9.2
1.09
0.98
Ga2O
1.02
0.20
2.89
GaAs
19.4
0.35
5.32
SiO2
2.1
0.71
2.76
Si
∞
0.31
2.33
Log Intensity (a.u.)
3
1
2
3
4
5
2 q (deg.)
http://prism.mit.edu/xray
Glancing Incident Angle Small Angle
X-ray Diffraction
Do quantum dots arrange themselves in a systematic manner with long range order?
What is the average distance between the quantum dots?
Intensity (a.u.)
10.056nm
5.901nm
5.150nm
3.924nm
88.27
58.85
44.14
35.31
29.43
25.22
d-spacing
(Å)
q
http://prism.mit.edu/xray
Microdiffraction
How does the diffraction pattern change at different positions on a sample?
http://prism.mit.edu/xray
Group classes are held regularly to train
you to use the X-ray lab independently
Training for Self-Use Requires
1 hour X-ray Safety Course from EHS
1 hour Lab Specific Safety Training
2 hr Instrument Specific Training
2 hr Practical XRD Lecture
3 hr Data Analysis Workshop
next session: late January or early February
see prism.mit.edu/xray for schedule updates
http://prism.mit.edu/xray
Assisted Use
I will gladly work with you to collect and
analyze data
usually needs to be scheduled ~2 weeks in
advance
http://prism.mit.edu/xray
Contact Information
Scott Speakman
office: 13-4009A
x3-6887
[email protected]
generally available 10 am to 4 pm
XRD Lab: 13-4027
XRD Computer Room: 13-4041
http://prism.mit.edu/xray
Upcoming IAP Lectures
Introduction to X-Ray Diffraction
Jan 17, 2-5 pm, room 13-2137
Nanocrystallite Size Analysis using XRD
Jan 24, 2-5 pm, room 13-2137
Thin Film Analysis using X-rays
Jan 31, 2-5 pm, room 13-2137
http://prism.mit.edu/xray
Workshops for Existing X-Ray Users
Basic Data Analysis with Jade
scheduled on request
Rietveld Refinement using HighScore Plus
Jan 29 and Jan 30, 1 to 5 pm
room 13-4041
RSVP by Jan 25
http://prism.mit.edu/xray