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The NHMFL-Pulsed Magnetic Field Facility at Los Alamos National Laboratory

The NHMFL-Pulsed Magnetic Field Facility at Los Alamos National Laboratory. C. H. Mielke Head of NHMFL-PFF User Program. NHMFL-PFF. Technical Area 35 . Technical Area 35 . General User Lab 124. Technical Area 35 . Cell 1: 50T 20 ms 50T 300 ms Cell 2: 50T 300 ms Cell 3: 65T 35 ms

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The NHMFL-Pulsed Magnetic Field Facility at Los Alamos National Laboratory

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  1. The NHMFL-Pulsed Magnetic Field Facility at Los Alamos National Laboratory C. H. Mielke Head of NHMFL-PFF User Program

  2. NHMFL-PFF Technical Area 35

  3. Technical Area 35

  4. General User Lab 124 Technical Area 35 Cell 1: 50T 20 ms 50T 300 ms Cell 2: 50T 300 ms Cell 3: 65T 35 ms Cell 4: 65T 35 ms Cell 5: 60T 60 ms Cell 6: test cell

  5. Technical Area 35

  6. New User Bank (NUB) • Current Bank • 1.6 MJ • 32 mF (4 mF increment) • 10 kV • 128 capacitors • 1 silicon switch • 6 cell switches • 1 charging supply • New Bank • 4.3 MJ • 33.6 mF (4.2 mF increment) • 16 kV • 56 capacitors • 4 silicon switches • 8 cell switches • 4 charging supplies Will cost $1.2M-$1.6M Will take 12-18 months to build Will enable B>65 T for users

  7. NHMFL-PFF Flagship Programs 60 T controlled waveform system MkII on-line Fall ‘05

  8. NHMFL-PFF Flagship Programs 60 T controlled waveform system MkII on-line Fall ‘05 Ultra-sound transmission Specific Heat Photo-luminescence Dilatometry Magnetization Resistivity GHz & MHz conductivity 3 w thermal difusivity

  9. 1 msec at 100T peak field 10 msec above 75T 2 second total pulse duration Capacitor Bank Tests Underway NOW 1m 2 MJ Cap Bank for 100T Magnet Magnetic Field environment will allow for short pulse like experiments

  10. Future Research Opportunities in Pulsed High Magnetic Field 60 T controlled waveform system MkII on-line ‘05 Ultra-sound transmission Specific Heat Photo-luminescence Dilatometry Magnetization Resistivity GHz & MHz conductivity 3 w thermal difusivity 100 T Multi-Shot magnet system on-line Fall ‘06 Resistivity Magnetiztion MHz Conductivity and more…

  11. 300 tesla Single Turn Project First test shot Open to users in October ‘05 First Shots will occur in about 2-4 weeks Extensive technique development underway Funded by LANL LDRD-DR program Containment tank 100 ton clamp 300 tesla single turn apparatus. 3.8 MA will be generated during the 6 msec field pulse. Single turn coil 60 kV collector plates

  12. Pulsed field GHz-frequency quantum oscillation measurements. Ross McDonald, Paul Goddard, Charles Mielke, Neil Harrison, John Singleton. (IHRP Funded) Tunable to frequency of interest Organic superconductor k-(BEDT-TTF)2Cu(SCN)2 Well separated resonant modes, Q-factor ~ 600@300K-1500@4.2K.

  13. GHz-frequency conductivity measurements of k-(BEDT-TTF)2Cu(SCN)2. (IHRP Funded) High fields reveal details of the Fermi-surface topology: both the a and b-orbits and stark quantum interference, b-a. a 64GHz, 2.1K b New pulsed field user program capability.

  14. DV gold layer 5 mm sample Magnetostriction in pulsed fields plastic capacitance dilatometer Diagram and picture of the dilatometer. Magnetic field is perpendicular to the dimension being measured. V. F. Correa, C. Mielke ~ NHMFL-LANL

  15. C. D. Immer et al., Phys. Rev. B 57, 71 (1997) 34.3 T 41.1 K N. Mushnikov et al., J. Phys.: Condens. Matter 16, 2395 (2004) Magnetostriction in a mid-pulse magnet. The voltage is proportional to the length change. The transition is clearly detected around 36 T. 40 80 T (K) YbInCu4: 1st order valence transition V. F. Correa, C. Mielke ~ NHMFL-LANL

  16. Thermal conductivity measurements using 3w technique in high magnetic field D. Kim, F. Balakirev, J. Betts, Albert Migliori (IHRP Funded) Thermal conductivity of Nd0.5Sr0.5MnO3 • 3w technique utilizes a heater fabricated on the sample. AC current at frequency w excites temperature variations at 2w, which in turn yields 3w voltage signal across the heater itself.

  17. Contactless Calorimeter rfAMC: Adaptation of 3-W technique (IHRP Funded) T. Coffey, D. Kim, C.H. Mielke • Thermodynamic measurement • via contactless conductivity • Strip heater ---> AM rf coil • Heater width --> sample width • Heat diffusion eqn. b>>D • Thermometer--> d in limit d << D • (dT -> ds -> d) Fig. 1: Cartoon of thermal penetration from a heater on a semi-infinite metallic sample • Fig 2: dc rfAMC Probe. • Sample-in/sample-out • Choice of vacuum or exchange gas

  18. Technology spinoffs from rfAMC Project T. Coffey, C.H. Mielke (IHRP Funded) Plug-N-Play Electronics User Friendly Pulsed Field TDO Probe • Super-heterodyne w/ different bandwidths • Amplifiers tailored for input to Super-Het • 1st stage of Amp. Integrated onto probe • Boards available to User Program • Therm. & pick-up leads integrated • Minimized cross talk • --> Gnd Plane

  19. RUS(resonant ultrasound spectroscopy)—resonances of small samples yield complete elastic tensor!This system is now routinely available for NHMFL users 290mK to 400K, 0-14T Sign up now for this exciting system!

  20. Field-induced Quantum Critical Point in Cubic CeIn3 dHvA and extraction magnetometry in pulsed magnetic fields Fig 2: Fermi surface with hot spots of high mass Fig 3: dHvA oscillations Fig 4: orientation and field-dependent mass Fig. 1: Camparison of the pressure (p) and magnetic field (B) dependent phase diagrams of CeIn3 T. Ebihara; Shizuoka U. N. Harrison, M. Jaime, J. Lasley; NHMFL - LANL

  21. Charge density wave systems in magnetic fields exceeding the Pauli limit. R.D. McDonald, N. Harrison, J. Singleton, A. Bangura, P.A. Goddard, L. Balicas, A.P. Ramires, X. Chi, Fully gapped CDW with finite interchain bandwidth such that both Landau quantization and the Zeeman splitting contribute to the Field dependence of the gap. Magnetoresistance of CDW system Per2Au(mnt)2 at fields exceeding the Pauli limit (B > 37T). In Per2Pt(mnt)2 the competition between localized spin dimerization and the CDW formation gives rise to structure in the field dependence of the gap. CDW gap closes but remains finite due to formation of a field modulated CDW state.

  22. High magnetic field as a bulk microscopic probe of the martensite phase in AuZn P A Goddard, R McDonald, J Singleton, J Lashley. First ever measurement of de Haas-van Alphen (dHvA) oscillations within a martensitic material. Oscillations measured at 100K - highest temperature dHvA yet observed. Comparison of data with band-structure calculation indicate electronic origin for shape memory effect. Typical oscillations Fermi surface can be traced across the transition, showing evolution of martensite phase. Co-existence of austenite and martensite at low temperature - bulk phase separation shown for the first time. Field dependence of effective Dingle temperature reveals information on the size of low-temperature domains.

  23. Upper critical field in LiTi2O4 Evangelia Moschopoulou (UC Davis) John Singleton, Paul Goddard (NHMFL) LiTi2O4 is an interesting spinel superconductor. But what is 0Hc2? Literature values (by extrapolation) range from 8-35 T! Solution: pulsed-field resistivity at NHMFL-LANL. Successful extraction of 0Hc2versus Tc. Alteration of valence increases Hc2 and Tc. Hc2versus Tc is “BCS-like”. • High-frequency lock-in data (1-10 A); • Fields >33 T needed to separate normal-state resistivity from dissipative vortex motion (humps, dips) in this granular superconductor.

  24. Hidden order/quantum criticality in U(Ru1-xRhx)2Si2 extraction magnetometry in pulsed magnetic fields and transport in the hybrid Fig 1: modification of the phase giagram (suppression of hidden order) and robustness of quantum criticality with Rh-doping Fig. 2: Nexus between quantum critical point, metamagnetic cross-over and transition temperature of phase II as a function of Rh doping J. Mydosh; Max-Planck H. Amitsuka; Hokkaido U. N. Harrison, M. Jaime, K.-H. Kim; NHMFL - LANL

  25. Probing quantum criticality in CexLa1-xMIn5 dHvA in pulsed magnetic fields, M = Co, Rh and Ir Fig 1: Evolution of the Fermi surface with Ce concentration and M: An itinerant 4f Fermi surface is observed only for M = Co and Ir for x = 1 Fig. 2: Ce dependence of the effective masses and mean free paths. A shorter mean free path for M = Co and Ir even in the dilute limit implies that quantum criticality is determined by differences in interactions present in single impurity case U. Alver, R. G. Goodrich, I Vekhter, R. T. Macaluso, J. Y. Chan; LSU L. Balicas, Z. Fisk, D. Hall; NHMFL - FSU N. Harrison, P. G. Pagliuso, N. O. Moreno, J. L. Sarrao; NHMFL - LANL

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