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![Page 1: Organic Superconductors At Extremes of High Magnetic Field Organic Superconductors At Extremes of High Magnetic Field C. H. Mielke Los Alamos National.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649cce5503460f9499a041/html5/thumbnails/1.jpg)
Organic SuperconductorsAt Extremes of High Magnetic FieldOrganic SuperconductorsAt Extremes of High Magnetic Field
C. H. MielkeLos Alamos National LaboratoryNational High Magnetic Field Laboratory
![Page 2: Organic Superconductors At Extremes of High Magnetic Field Organic Superconductors At Extremes of High Magnetic Field C. H. Mielke Los Alamos National.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649cce5503460f9499a041/html5/thumbnails/2.jpg)
Organic SuperconductorsAt Extremes of High Magnetic Field
C. H. MielkeLos Alamos National LaboratoryNational High Magnetic Field Laboratory
NHMFL
![Page 3: Organic Superconductors At Extremes of High Magnetic Field Organic Superconductors At Extremes of High Magnetic Field C. H. Mielke Los Alamos National.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649cce5503460f9499a041/html5/thumbnails/3.jpg)
![Page 4: Organic Superconductors At Extremes of High Magnetic Field Organic Superconductors At Extremes of High Magnetic Field C. H. Mielke Los Alamos National.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649cce5503460f9499a041/html5/thumbnails/4.jpg)
NHMFL Magnetic Field Capabilities
• Explosively Driven– 145 T flux compression generator (~3 kg detasheet)– 800-1000 T fcg cylindrical symmetry (~20 kg HMX-9501)– 300 T Capacitor Driven exploding coils
• Controlled Waveform 90 MJ (650 MJ max)– 60T 2 second controlled waveform– 100T CW outsert CD insert 145 MJ (available 2004)
• Capacitor Driven 0.6-1.2 MJ (1.6 MJ max)– 60T “short pulse” 6ms rise 40ms decay– 50T “mid-pulse” 40ms rise 300ms decay
• DC Superconducting Magnets (to 20T)
![Page 5: Organic Superconductors At Extremes of High Magnetic Field Organic Superconductors At Extremes of High Magnetic Field C. H. Mielke Los Alamos National.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649cce5503460f9499a041/html5/thumbnails/5.jpg)
“Fowler” Flux compressors• Max field of ~180T
• 10mm to 20mm bore
• High homogeneity
• Sample & cryostat are destroyed
• 3 kg of sheet explosive140
120
100
80
60
40
20
0100x10
-6806040200
Time (seconds)
10MT/s
5
0
-5
-10
![Page 6: Organic Superconductors At Extremes of High Magnetic Field Organic Superconductors At Extremes of High Magnetic Field C. H. Mielke Los Alamos National.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649cce5503460f9499a041/html5/thumbnails/6.jpg)
• Explosively Driven– 145 T flux compression generator (~3 kg detasheet)– 800-1000 T fcg cylindrical symmetry (~20 kg HMX-9505)– 300 T Capacitor Driven exploding coils
• Controlled Waveform 90 MJ (650 MJ max)– 60T 2 second controlled waveform– 100T CW outsert CD insert 145 MJ (available 2004)
• Capacitor Driven 0.6-1.2 MJ (1.6 MJ max)– 60T “short pulse” 6ms rise 40ms decay– 50T “mid-pulse” 40ms rise 300ms decay
• DC Superconducting Magnets (to 20T)
NHMFL Magnetic Field Capabilities
![Page 7: Organic Superconductors At Extremes of High Magnetic Field Organic Superconductors At Extremes of High Magnetic Field C. H. Mielke Los Alamos National.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649cce5503460f9499a041/html5/thumbnails/7.jpg)
Multi-Stage Flux Compression Generators
• Russian Design “MC1” FCG
• 800 to 1000 tesla
• 20 kg shaped explosive (PBX 9501) 95% HMX 9505 and 5% Plastic bonder
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Multi Stage Flux Compression
800
600
400
200
0
Magnetic Field Intensity (tesla)
74x10-6
706866646260
Time (seconds)
First Cascade Accelerates
Second Stage Fuses
Shock Wave Hits
MC-1 Flux Compression GeneratordB/dT ~ 150 MT/sec
![Page 9: Organic Superconductors At Extremes of High Magnetic Field Organic Superconductors At Extremes of High Magnetic Field C. H. Mielke Los Alamos National.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649cce5503460f9499a041/html5/thumbnails/9.jpg)
• Explosively Driven– 145 T flux compression generator (~3 kg detasheet)– 800-1000 T fcg cylindrical symmetry (~20 kg HMX-9505)– 300 T Capacitor Driven exploding coils
• Controlled Waveform 90 MJ (650 MJ max)– 60T 2 second controlled waveform– 100T CW outsert CD insert 145 MJ (available 2004)
• Capacitor Driven 0.6-1.2 MJ (1.6 MJ max)– 60T “short pulse” 6ms rise 40ms decay– 50T “mid-pulse” 40ms rise 300ms decay
• DC Superconducting Magnets (to 20T)
NHMFL Magnetic Field Capabilities
![Page 10: Organic Superconductors At Extremes of High Magnetic Field Organic Superconductors At Extremes of High Magnetic Field C. H. Mielke Los Alamos National.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649cce5503460f9499a041/html5/thumbnails/10.jpg)
60
50
40
30
20
10
02.01.51.00.50.0
Time (seconds)
NHMFL 60 tesla controlled waveform magnet
100 ms flat top 200 ms flat top Stepped fiels (Specific Heat Experiments)
Specific Heat in a Kondo InsulatorJaime, et al, Nature 405 (2000) 160
60 minutes between full field shots
1.4 GW motor-generator
1m90 MJ of energy
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• Explosively Driven– 145 T flux compression generator (~3 kg detasheet)– 800-1000 T fcg cylindrical symmetry (~20 kg HMX-9505)– 300 T Capacitor Driven (CD) exploding coils
• Controlled Waveform (CW) 90 MJ (650 MJ max)– 60T 2 second controlled waveform– 100T CW outsert CD insert 145 MJ (available 2004)
• Capacitor Driven 0.6-1.2 MJ (1.6 MJ max)– 60T “short pulse” 6ms rise 40ms decay– 50T “mid-pulse” 40ms rise 300ms decay
• DC Superconducting Magnets (to 20T)
NHMFL Magnetic Field Capabilities
![Page 12: Organic Superconductors At Extremes of High Magnetic Field Organic Superconductors At Extremes of High Magnetic Field C. H. Mielke Los Alamos National.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649cce5503460f9499a041/html5/thumbnails/12.jpg)
Specifications
Outer Coil (125 MJ peak energy) (Department of Energy)
Coils 1 through 4 AL-60 Conductor 301 SS Sheet Reinforcement wound on Nitronic-40 bobbin
Coils 5 and 6 AL-15 Conductor Nitronic-40 Monolithic Reinforcement
Coil 7 Hard Cu Conductor 304 SS Monolithic Reinforcement
One Meter
Design and Materials
NHMFL’s 100 T Multi-Shot Magnet
100T peak field15mm borePulse every hour
1 msec at 100T peak field
2 secondtotal pulse duration
Insert Coil (2 MJ peak energy) (National Science Foundation) CuNb Conductor MP35N Sheet Zylon Fiber Reinforcement
10 msec above 75T
140 MJ of energy
![Page 13: Organic Superconductors At Extremes of High Magnetic Field Organic Superconductors At Extremes of High Magnetic Field C. H. Mielke Los Alamos National.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649cce5503460f9499a041/html5/thumbnails/13.jpg)
• Explosively Driven– 145 T flux compression generator (~3 kg detasheet)– 800-1000 T fcg cylindrical symmetry (~20 kg HMX-9505)– 300 T Capacitor Driven exploding coils
• Controlled Waveform 90 MJ (650 MJ max)– 60T 2 second controlled waveform– 100T CW outsert CD insert 145 MJ (available 2004)
• Capacitor Driven 0.6-1.2 MJ (1.6 MJ max)– 60T “short pulse” 6ms rise 40ms decay– 50T “mid-pulse” 40ms rise 300ms decay
• DC Superconducting Magnets (to 20T)
NHMFL Magnetic Field Capabilities
![Page 14: Organic Superconductors At Extremes of High Magnetic Field Organic Superconductors At Extremes of High Magnetic Field C. H. Mielke Los Alamos National.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649cce5503460f9499a041/html5/thumbnails/14.jpg)
60 tesla “short pulse”
• ~6 milli-seconds to peak field
• Work-horse of the magnet lab
• Life-time of ~500 full field shots
10 cm
30 minutes between full field shots
0.6 MJ of energy
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Normal Mode of Failure
• Causes minor damage– He dewar tail– Probe insert– LN2 bucket (igloo cooler)
• Fault on lead end or sometimes in the 3rd layer midplane (due to fatigue of conductor)
• Audible report
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Short Pulse Stress Failure
60 tesla magnet destroyed at 72 tesla “confinement failure”
0.8 MJ of energy
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Worth the hassle for condensed matter physics
• Extreme fields quantize quasi-particle orbits
• Split Energy Bands
• Suppress Superconductivity
• Drive magnetic transitions
• Reveal new states of matter
• Ect., ect., etc….
5.0x10-8
4.5
4.0
3.5
3.0
6050403020100
Magnetic Field (tesla)
α-( - )BEDT TTF 2 ( )KHg SCN4 = 400 T mK
rf contactless conductivityƒ = 28 MHz
10-4
10-3
10-2
10-1
100
6000500040003000200010000
Frequency (tesla)
β
β−αβ+α
4α
β−α
3α2α
α
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Organic Superconductors
• First Organic Superconductor Discovered in 1979
• Initial Tc of ~1K– Q1-D salt
• Various categories– “Bucky Balls”– FET types– Charge transfer salts
TetraMethylTetraSelenaFulvalene
cloride Tc=1K
-BisEthyleneDiThio-TetraThioFulvalene
Copper ThioCynate Tc=10K
-BisEthyleneDiThioTetraThioFulvalene
copper DiCyanidBromide Tc=11.6K
-BisEthelyneDiThioTetraSelenaFulvalene
Gallium TetraClorate Tc= 5K
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Charge Transfer Salts begin with organic radicals
BEDT-TTF based (ET for short)
BEDT-TSF based (BETS for short)S
Se
Se
S
Se
S
S
Se
H
HHH
S
S
S
S
S
S
S
S
H
HHH
![Page 20: Organic Superconductors At Extremes of High Magnetic Field Organic Superconductors At Extremes of High Magnetic Field C. H. Mielke Los Alamos National.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649cce5503460f9499a041/html5/thumbnails/20.jpg)
Effect of the Inorganic Anion
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Organic meets Inorganic-(BEDT-TSF)2GaCl4
Half of the unit cell
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The Unit Cell
-(BEDT-TSF)2GaCl4 -(BEDT-TTF)2Cu(NCS)2
a = 18 Åb = 16 Åc = 8 Å
a = 16 Åb = 8 Åc = 13 Å
Layer spacing is the important dimension
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packing motif packing motif
The Fermi Surfaces
β
α
Γ
M
k
kc
b
Y
-(BEDT-TSF)2GaCl4 -(BEDT-TTF)2Cu(NCS)2
![Page 24: Organic Superconductors At Extremes of High Magnetic Field Organic Superconductors At Extremes of High Magnetic Field C. H. Mielke Los Alamos National.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649cce5503460f9499a041/html5/thumbnails/24.jpg)
Anisotropy of the Electronic System
-(BEDT-TTF)2Cu(NCS)2-(BEDT-TTF)2Cu(NCS)2
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Molecular Corridor-(BEDT-TSF)2GaCl4
![Page 26: Organic Superconductors At Extremes of High Magnetic Field Organic Superconductors At Extremes of High Magnetic Field C. H. Mielke Los Alamos National.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649cce5503460f9499a041/html5/thumbnails/26.jpg)
4
3
2
1
06050403020100
Field (tesla)
1.0
0.8
0.6
0.4
0.2
0.0800040000
Frequency (tesla)
αƒ=670 T
βƒ=4060 T
0.10
0.05
0.00
-0.05
-0.1026 10x -324222018
1/μ0 (H T-1)
-( - )BEDT TSF2GaCl4 = 430 T mK
Magnetic Breakdown in -(BEDT-TSF)2GaCl4
![Page 27: Organic Superconductors At Extremes of High Magnetic Field Organic Superconductors At Extremes of High Magnetic Field C. H. Mielke Los Alamos National.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649cce5503460f9499a041/html5/thumbnails/27.jpg)
Magnetic Breakdown in -(BEDT-TTF)2Cu(NCS)2
1.0
0.5
0.0
-0.5
36x10-3
34323028262422
Inverse Magnetic Field (T-1
)
T = 40 mK
T = 650 mK
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Magnetic Breakdown1.0
0.8
0.6
0.4
0.2
0.01000080006000400020000
Frequency (tesla)
α = 600 T
β = 3990 Tβ − α
Pippard Magnetic Breakdownβ
α
Γ
M
k
kc
b
Y
![Page 29: Organic Superconductors At Extremes of High Magnetic Field Organic Superconductors At Extremes of High Magnetic Field C. H. Mielke Los Alamos National.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649cce5503460f9499a041/html5/thumbnails/29.jpg)
Exponential Growth of Breakdown Amplitude
4x10-3
2
0
-2
-4
42x10-3
4038363432302826
Inverse Magnetic Field ( T-1
)
-( - )BEDT TTF 2 ( )Cu NCS4 Breakdown orbit digitally filtered = 40T mK
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Forbidden Trajectories0.25
0.20
0.15
0.10
0.05
0.001000080006000400020000
Frequency (tesla)
β
β + α
β − α
β + 3αβ − 2α
-( - )BEDT TTF 2 ( )Cu NCS4
β − α α
Γ
Mk
k
Y
Anomalous Trajectories are due toStark Quantum Interference
β
α
Γ
M
k
kc
b
Y
![Page 31: Organic Superconductors At Extremes of High Magnetic Field Organic Superconductors At Extremes of High Magnetic Field C. H. Mielke Los Alamos National.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649cce5503460f9499a041/html5/thumbnails/31.jpg)
Angular Dependent Magnetoresistance
Field Lines
PlatformSample
Rotation Axis
-(BEDT-TSF)2GaCl4
-(BEDT-TTF)2Cu(NCS)2
B = 42T (DC)
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B
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Belly orbits show salt to be more 3-D than
Quasi 2-D region w/B || layersPeak width is determinedby the interlayer transfer integral (t )
β
α
Γ
M
k
kc
b
Y
J. Singleton, et. al. PRL, 88 (2002).
t⊥λ ≈0.21meV
t⊥κ ≈0.04meV
C. Mielke, et. al. J. Phys. Cond. Mat., 13 (2001) 8325.
Tight-binding dispersion relation added to the effective dimer model
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Using G-L theory to estimate z
302520151050
Magnetic Field (tesla)
H c2 c2H
H || planes
-( )ET 2 ( )Cu NCS4 -( )BETS 2GaCl4
Hc2⊥z =φ0
2πξxyξz
z ≈ 5Å
z ≈ 16Å
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At T* ≈ 18 Å for -(BEDT-TSF)2GaCl4
10
2
3
4
5
6
7
89
100
43210
Temperature (K)
( ) ~ T (0)/(1 - )t1/2
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4
5
6
7
89
10
2
3
4
5
Coherence Length (Å)
86420
Temperature (K)
-(BEDT-TTF)2Cu(NCS)2 appears to be in the 2-D limit so close to Tc we can’t resolve it
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Superconducting Properties of -(BEDT-TSF)2GaCl4
and -(BEDT-TTF)2Cu(NCS)2
C. H. Mielke, J. Singleton, M-S Nam, N. Harrison, C.C. Agosta, B. Fravel, and L.K. Montgomery, J. Phys.: Condens. Matter, 13 (2001)8325.
6
5
4
3
2
1
01086420
Temperature (K)
-( )ET 2 ( )Cu NCS2
(Fit to Tc- )Tβ
β =0.73
λ-(BEDT-TSF)2GaCl4 Fit to (Tc-T)
β
β = 0.5 G-L theory 3D linear fit
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Conclusions
• Creating very high magnetic fields can be exciting!
• By tuning the organic molecules the effective dimensionality of the system is readily changed
• Dimensionality is closely related to the superconducting properties
John Singleton (Oxford U. joining LANL in July)Ross McDonald (LANL Postdoctoral Fellow 3-D Fermi surfaces)Greg Boebinger, Dwight Rickel, Neil Harrison (LANL)Mike (L. K.) Montgomery (Indiana U. synthesis of organic SC) Department of Energy and the National Science Foundation