# Presentation: 479268

## Organic Superconductors

- At Extremes of High Magnetic Field

- At Extremes of High Magnetic Field

- C. H. Mielke
- Los Alamos National Laboratory
- National High Magnetic Field Laboratory

## Organic Superconductors

- At Extremes of High Magnetic Field

- C. H. Mielke
- Los Alamos National Laboratory
- National High Magnetic Field Laboratory

- NHMFL

## Slide 3

## 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)

## “Fowler” Flux compressors

- Max field of ~180T
- 10mm to 20mm bore
- High homogeneity
- Sample & cryostat are destroyed
- 3 kg of sheet explosive

## 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)

- 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

## 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

## Multi Stage Flux Compression

## 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)

- 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

## 1.4 GW motor-generator

**Specific Heat in a**
** ****Kondo Insulator**
***Jaime, et al,   ***
***Nature  405 (2000) 160***

- 60 minutes between full field shots

- 1m

- 90 MJ of energy

## 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)

- 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

## 140 MJ of energy

- 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 field
- 15mm bore
- Pulse every hour

- 1 msec
- at 100T
- peak field

- 2 second
- total
- pulse duration

- Insert Coil  (2 MJ peak energy)
-    (National Science Foundation)
**    ****CuNb Conductor**
**    ****MP35N Sheet**
**    ****Zylon Fiber Reinforcement**

- 10 msec
- above 75T

## 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)

- 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

## 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

## 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

## Short Pulse Stress Failure

- 60 tesla magnet destroyed at 72 tesla “confinement failure”

- 0.8 MJ of energy

## 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....

## 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

## Charge Transfer Salts begin with organic radicals

- BEDT-TTF based (ET for short)

## Effect of the Inorganic Anion 

## Organic meets Inorganic

- -(BEDT-TSF)2GaCl4

- Half of the unit cell

## The Unit Cell

- -(BEDT-TSF)2GaCl4

- -(BEDT-TTF)2Cu(NCS)2

- a = 18 Å
- b = 16 Å
- c = 8 Å

- a = 16 Å
- b = 8 Å
- c = 13 Å

- Layer spacing is the important dimension

## The Fermi Surfaces

- -(BEDT-TSF)2GaCl4

- -(BEDT-TTF)2Cu(NCS)2

## Anisotropy of the Electronic System 

- -(BEDT-TTF)2Cu(NCS)2

- -(BEDT-TTF)2Cu(NCS)2

## Molecular Corridor

- -(BEDT-TSF)2GaCl4

## Magnetic Breakdown in-(BEDT-TSF)2GaCl4

- Magnetic Breakdown in-(BEDT-TSF)2GaCl4

## Magnetic Breakdown in-(BEDT-TTF)2Cu(NCS)2

- Magnetic Breakdown in-(BEDT-TTF)2Cu(NCS)2

- T = 40 mK

- T = 650 mK

## Magnetic Breakdown

- Pippard Magnetic Breakdown

## Exponential Growth of Breakdown Amplitude

## Forbidden Trajectories

## Angular Dependent Magnetoresistance

- -(BEDT-TSF)2GaCl4

- -(BEDT-TTF)2Cu(NCS)2

- B = 42T (DC)

**B**

- 

## Belly orbits show  salt to be more 3-D than  

- Belly orbits show  salt to be more 3-D than 

- Quasi 2-D region w/B || layers

- Peak width is determined
- by the interlayer transfer
- integral (t  )

- J. Singleton, et. al. *PRL*, **88** (2002).

- C. Mielke, et. al. *J. Phys. Cond. Mat.*, **13** (2001) 8325.

- Tight-binding dispersion relation added to the effective dimer model

## Using G-L theory to estimate z

- z ≈ 5Å

- z ≈ 16Å

## At T*  ≈ 18 Å for -(BEDT-TSF)2GaCl4

## -(BEDT-TTF)2Cu(NCS)2 appears to be in the 2-D limit so close to Tc we can’t resolve it 

- -(BEDT-TTF)2Cu(NCS)2 appears to be in the 2-D limit so close to Tc we can’t resolve it

## 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.

## 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