Plenary lecture of the XIV SBPMat Meeting, given by Prof. Ichiro Takeuchi (University of Maryland, USA) on September 30, 2015, in Rio de Janeiro (Brazil).
1. No impurity Ti (3 Å) Ti (6 Å) Ti (9 Å) Cu (3 Å) Cu (6Å) Cu (9 Å)
5 Å
10 Å
15 Å
20 Å
25 Å
35Å
45 Å
55 Å
ti(Å)
ts(Å)
Permanent magnet library
Ferroelectric library
Superconductor library
Ichiro Takeuchi
University of Maryland
Combinatorial Approach to
Materials Discovery
2. • Introduction to the combinatorial approach:
brief history, tools and strategies
• Integrated materials discovery engine
• Recent examples: combinatorial search of
rare-earth-free permanent magnets;
superconductors
Outline
3. University of Maryland
Tieren Gao
Sean Fackler
Kui Jin
R. Greene
SLAC
A. Mehta
US DOE, ONR, AFOSR
Support
Acknowledgement
Duke University
S. Curtarolo
Ames Lab
M. J. Kramer
NIST
A. G. Kusne
M. Green
7. Combinatorial Libraries of Inorganic Materials
Luminescent
materials libraries,
Science 279,
1712 (1998)
Semiconductor gas sensor library,
“electronic nose”,
Appl. Phys. Lett. 83, 1255 (2003)
Magnetic shape memory alloy library,
Nature Materials 2, 180 (2003)
8. Fabrication of libraries and spreads
Combinatorial PLD systems – metal oxides
Combinatorial UHV sputtering system – metallic alloys
Combinatorial multigun e-beam evaporator system – metal
Combinatorial laser MBE – metal oxides
Rapid characterization tools
Scanning SQUID microscopes – magnetic properties
Scanning microwave microscopes – resistive, magnetic, dielectric
Scanning X-ray microdiffractometer
Magneto-optical Kerr effect (MOKE) system – magnetic properties
Scanning 4-point probe station – transport
Novel device libraries incorporating MEMS, etc.
Major Facilities for Combinatorial
Materials Research at Maryland
Focus: Functional Thin Film Materials
9. Correlation between materials complexity
and physical properties
Hg
Nb3Ge
La2CuO4
YBa2Cu3O7
HgBa2CaCu3O7
CriticalTemp.(K)
30
60
90
120
150
180
210
240
1
Number of Elements
2 3 4 5 6 7
23. A B
C ED
# depositions: 4 x n
# combinations: 4n
5 masks:
4 x 5 = 20 depo’s
45 = 1024 samples
24. (Right) Luminescent image of the same library after thermally
processed under UV excitation.
Science 279, 1712 (1998)
Library of luminescent materials made w/ quaternary masking
25. Various combinatorial experimental designs:
discrete libraries vs composition spreads
Composition A B
B
A
C
• Composition spreads allow continuous mapping of physical properties
and phase boundaries
• Run to run variation in ordinary experiments is removed
28. Takeuchi et al.,
Applied Physics Letters 79, 4411 (2001)
Scanning Microwave Microscope:
a rapid characterization tool
Originally developed for rapid screening of
libraries of superconductors, dielectric materials, etc.
SampleTip
Coaxial ¼
resonator
x-y-z stage Motion
controller
Computer
f0
Q
Microwave
source
Review Article: Gao, et al., Measurement Science and Technology 16, 248 (2005)
29. -250
-200
-150
-100
-50
0
50
100
150
200
880 890 900 910 920 930 940 950 960 970
Magnetic field (Oe)
FMRsignal(arb.unit)
2.45 GHz
SrTiO3
BaTiO3
CaTiO3
500
400
100
300
0
200
r
Different physical properties can be mapped using
an existing microwave microscope
Dielectric constant mapping
of a (Ba,Sr,Ca)TiO3 pseudo-
ternary library at 1 GHz
Appl. Phys. Lett. 74, 1165 (1999)
Ferromagnetic resonance (FMR)
signal taken at a spot
Dielectric
property
Magnetic property
(spin resonance)
composition plot
30. Mode/materials
[reference]
Physical parameter/
phenomenon
Spatial
resolution
Dielectric [12-14] Complex dielectric
constant
100 nm
Metal [13] Impedance/resistivity 100 nm
Non-linear
dielectric [15,18]
Non-linear dielectric
constant
1 nm
FMR Ferromagnetic
resonance
100 nm*
STM-ESR Electron
spin resonance
Atomic
resolution
Capabilities of Multiscale Microwave Microscope
Mapping of various physical properties can be obtained
at macroscopic scale (~ 1 cm) down to the listed spatial resolution
32. Composition Spreads of
Ternary Metallic Alloy Systems
Co-sputtering scheme Ni
Mn
Al
3” spread wafer
Ni Al
Mn
Phase diagram
Composition is mapped using an electron probe (WDS)
33. RT Scanning SQUID microscope
(Magma, Neocera)
SQUID assembly
inside vacuum
leveling probe and
scanning stage
Room temperature samples are measured
z-SQUID is used to
measure Bz distribution
Tip-sample distance is typically 100~200 microns
36. Rapid detection of shape memory alloy
compositions by visual inspection
Composition spread
deposited on
micromachined
cantilever array
Film thickness
~0.5 m
Detection of martensitic phase transformation
37. Functional phase diagram of Ni-Mn-Ga
20 40 80
20
40
60
80
60
80
20
Mn
40
20 40 80
20
40
60
80
Ni
60
80
20
40
Ni2Ga3 Ga
Increasing
transition
temperature
Ferromagnetic
regions
Most strongly
magnetic
Martensites
Nature Materials 2, 180 (2003)
38. Integration of theory and high-throughput experiments
Step 2 Step 3Step 1
Integrated materials discovery engine
Experimental
Track
Theoretical
Track
39. Step 2 Step 3Step 1
Experimental
Track
Theoretical
Track
Advantages of this approach:
Predictions are sometimes “off” by stoichiometric variations.
Integration of theory and high-throughput experiments
40. Step 2 Step 3Step 1
Experimental
Track
Theoretical
Track
Advantages of this approach:
Predictions are sometimes “off” by stoichiometric variations.
Large number of data points in combinatorial experiments suitable
for building models.
Integration of theory and high-throughput experiments
42. Step 2 Step 3Step 1
Experimental
Track
Theoretical
Track
Example:
Rare‐earth‐free permanent magnets
APL 102, 022419 (2013);
Scientific Reports 4, 6367 (2014)
Integration of theory and high-throughput experiments
43. Rare-earth (Nd, Dy, Sm, etc.)-free magnets are
needed due to their fluctuating prices
Search for new permanent magnet materials
w/o rare-earth elements
The prices of many rare‐earth
metals have increased by
more than 10 fold in the past
few years
Permanent
magnets for:
direct drive wind
turbines
Current magnets: Nd‐Fe‐B, Sm‐Co
Advanced
electric
drive motors
44. History of development of permanent magnets
Best magnets contain rare-earth elements: Nd, Dy, Sm
Nd-Fe-B
Sm-Co
Year
56. Exploration of new superconductors: Fe-B
composition spread
3” wafer
Fe rich B rich
16 spot 4‐terminal
pogo pin arrays:
Cut wafers into 1
cm2 pieces and
measure 16 spots
at once
Color change tracks:
composition change, crystallinity
change, and metal to insulator transition
57. Fe-B composition spread: Fe-rich side, 16 spots on one 1 cm2 chip
Ch 113” wafer
more Bmore Fe
temperature
resistance
4.2 K 300 K
All metallic
59. Ch 11
Ch 3
Ch 13
Middle region:
FeB2 – FeB4
more Bmore Fe
temperature
resistance
4.2 K 300 K
Fe-B composition spread: FeBx(x =2-4), 16 spots on one 1 cm2 chip