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ENHANCEMENTS 2008-2009 I. Completed addition of 10T-10 mK facility

NHMFL High B/T Facility - Gainesville. ENHANCEMENTS 2008-2009 I. Completed addition of 10T-10 mK facility --- annex to Microkelvin Laboratory fast turn-around, test samples, cells prior to use in ultra-low temperature

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ENHANCEMENTS 2008-2009 I. Completed addition of 10T-10 mK facility

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  1. NHMFL High B/T Facility - Gainesville ENHANCEMENTS 2008-2009 I. Completed addition of 10T-10 mK facility --- annex to Microkelvin Laboratory fast turn-around, test samples, cells prior to use in ultra-low temperature High B/T Facility (0.25mk, 16 T) II. Extended NHML user to Bay 2 of Microkelvin Laboratory (0.05mk, 8T). Seeking research scientist to provide needed staff III.In Progress: New 20T magnet (Cryomagnetics Inc.) Aug. completion of inner-most Nb3Sn insert coil Sep. completion of all Nb3Sn coils Oct. Completion of 20 T and demag coil set Nov.-Dec. Final assembly and testing Delivery ---- end of Dec. 2009

  2. Schematic View of the High-B/T Facility

  3. Scientific Mission of the Facility Dedicated to high-B experiments requiring T< 20 mK Experiments generally require a quiet environment and/or a long coolingtime. High Magnetic Field B = 15.3/16.5 T ( upgrade to 20 T, 2009 Homogeneity 1.6x10-5 10 mm DSV < 3x10-3 over 100 mm axial length 30 mm-dia bore, 25 mm-dia experimental space Ultra-Low Temperature 5 mole PrNi5 (nuclear refrigerant), Tmin < 0.4 mK 8 nW cooling power, t > 6 weeks @ 1 mK (world’s largest) CAPABILITIES:Method for Highest B/T

  4. Capabilities and Specialized Instruments Electrical Transport Measurements High frequency Pulsed NMR (300 MHz – 1.6 GHz) Ultrasound High sensitivity bridges Vibrating-wire viscometers Sample rotator (–10 to +90, with a liq-3He actuator) Low temperature RF pre-amplifier -- NMR applications Thermometry Pt NMR T < 20 mK, in low B space 3He melting curve thermometer 0.4 mK < T Vibrating-wire thermometer 1.7 mK < T Kapton capacitance thermometer 4 mK < T CMN susceptibility thermometer 15 mK < T, in low B space RuO2 resistor (all commercial) 20 mK < T, in low B space Instrumentation

  5. Rotator sample rotator heat exchanger HIGH B/T CAPABILITIES: Ultra-Low T ROTATOR

  6. HIGHB/T CAPABILITIES: NMR Cell HIGH B/T Instruments: NMR Cell NMR up to 16 T : Studies of quantum diffusion of 3He in superfluid 4He for high nuclear spin polarization. Re-entrant cavity with walls at relatively high temperature and sample in cold finger inside cavity

  7. NEW CAPABILITIY: LOW TEMPERATURE AMPLIFIER HIGH B/T Instruments: NMR Cell Uses HEMT transistor (simple source follower) can operate to ~ 0.3 K T Noise ≤ 1 K C. Huan, et al. J. Low Temp Phys. (in press) First application: low frequency NMR at ultra-low T

  8. Crossed-Coil NMR Probe: low frequency, low gamma S. S. Kim, C. Huan et al. J. Low Temp. Phys. (in press) amplifier standoffs NMR cell Pulse B1, create transverse Magnetization in receiving coil

  9. 2008-2009 Users and Experiments • 1. FQHE of n=5/2 and 7/2 States in High Density Sample. • W. Pan (Sandia Nat. Lab.), D.C. Tsui (Princeton) • 2. Supersolid4He and NMR of 3He Impurities • D. Candela et al. (U. Mass.). • 3 & 4. BEC and Quantum Phase Transitions in S=1 Antiferromagnet. • V. Zapf et al. (LANL) • 5. Charge Carrier Density Variation 5/2 Fractional Quantum Hall Effect • W. Pan (Sandia )D. Tsui (Princeton University) • Systematic investigation of the metal-insulator transition at • ultra low temperatures in p-type GaAs FET structures. •   D. Luhman, D.C. Tsui (Princeton Univ.) • 7. Magnetic Interactions of Novel Materials at Low T/High B. • M.W. Meisel (UF), A. Feher et al. (Šafárik Univ., Košice, Slovakia). • 8. Search for long-range magnetic order in weakly coupled quantum S=1/2 chain system • T. Hong and A. Zheludev, NSSD, ORNL • High sensitivity dielectric measurements supersolid 4He • M. Chan et al. Penn State U. Bay 3 Bay 3 Bay 3 & Wm Annex Bay2 Wm Annex Wm Annex Wm Annex

  10. 2009 Future Users and Experiments • 1. Magnetization Studies of NFL Ground State of CeCoIn5 • A. McCollam & S.R. Julian (U. Toronto) • Dielectric susceptibility studies of supersolid 4He • M. Chan, (PSU), L. Yin et al. (UF) • 3. Search for Half-Metallic Ground State in Quasi-One Dimensional Magnet • Xiao-Dong Wen, Thomas J. Cahill, Roald Hoffmann (Cornell) Bin Zhang (Chinese Academy of Sciences) • 4. Studies of Magnetic PN Junctions . • N. Rangaraju, B. Wesson (NthWestern Univ.) • 5. Quantum Tunneling in Molecular Magnets • N. Dalal (FSU) • 6. Two-dimensional metallic states –GaAs Quantum Wells) • S. Tozer et al. (FSU, NHMFL) • 7. High B Studies of Paramagnetically Doped materials • M.H. Levitt, Univ. of Southampton) Bay 2, Oct. 09 Wm Hall Annex, Sep. 09 Bay 3, Jan.? 09 Interest/Proposal Pending Request/Proposal in Prep. Interest/Proposal Pending Interest/Proposal Pending

  11. Science Highlights 1 NMR Studies of Dilute 3He in Solid 4He and Test of proposed Supersolid state. D. Candela (Univ. of Massachusetts),Sung Su Kim, Chao Huan, Liang Yin, Jian-sheng Xia et al. University of Florida and NHMFL. NMR measures quantum tunneling of 3He impurities in solid 4He: Low T values of T2 give 3-4 quantum exchange rates: Strongly dependent on impurity concentration interaction V=Vo/Rn short range -- best fit long range Support: NHMFL Collab. Grants Res. Program S. S. Kim, C. Huan et al., J. Low Temp. Phys. (in press)

  12. Science Highlights 2 Interplay of Frustration and Magnetic Field in 2D Quantum Antiferromagnet A. Orendáčová et al., University, Košice, Slovakia; M. W. Meisel et al., NHMFL. Cu(tn)Cl2 (tn = C2H10N2): S = ½ anisotropic 2D highly frustrated magnet: square lattice with nn J (= 3 K), frustrating nnn J′ (< 0.6 J), weak interlayer J′′ (~ 10−3 J) Max. peak Heat capacities structure idealized Test BKT model for ideal square lattice: vortex-antivortex (V-AV) binding at low T,B with transition to spin gap at Bsat A. Orendáčová et al., PRB (submitted), arXiv:0906.3181 BKT calculation (Cuccoli et al. PRB 68 (2003)). χac at NHMFL-UF Wm 123 Facility. All other symbols from Cv analysis. Acknowledgements: VEGA (1/0078/09, APVV-0006-07), ESF RNP , NSF DMR-0701400, DMR-0654118, State of Florida, Deutsche Physikalische Gesellschaft (DPG), EuroMagNET II, US Steel Košice s.r.o. High B/Low T susceptibility measurements

  13. Bose-Einstein Condensation Universality Class NiCl2- 4SCs(NH2)2 at Ultra-Low T V.S. Zapf L. Yin et al. , A. Padhuan-Filho Ni S=1 spins: 3D XY anti-ferromagnet --- critical fields: Hc1 ~ 2 T, Hc2 ~12 T. Expectpower-law T dependence: Hc1(T) -- Hc1(0) = aT with  = 1.5 Confirmed at mK temperatures with a=1.470.01 Unit cell of tetragonal NiCl2–4SCs(NH2)2 Science Highlights 3 AC susceptibilty measurements, NHMFL High B/T facility L. Yin et al., Phys. Rev. Lett. 101,187205 (2008)

  14. Disorder driven gapless superfluid in high porosity aerogel : Ultrasound measurements Y. Lee et al., Phys. Rev. Lett. 98, 225301 (2007). Science Highlights 4 Tunneling exp. cannot be done for superfluid. BUT w-dependence of ultrasound attenuation can provide similar info. ? Sharma and Sauls, Physica B (03)

  15. Growth of Users and CostsHigh B/T Facility (2005-2009 Liquid helium costs (k$) No. Users/Yr added part Bay 2 Support (10 k$)

  16. 20+ Tesla Upgrade:Comparisons

  17. Personnel High-B/T Personnel • Program Manager: Jian-Sheng Xia ………….U.F. Res. Scientist • Postdoctoral Assoc: Liang Yin………………...NHMFL supported • Bay 2 Manager: Naoto Masuhara…............U.F. Engineer • Program assistant: Darlene Latimer…………U.F. Staff • Microkelvin Lab Director : Neil Sullivan ……….U.F. Faculty • Affiliated faculty (Physics): • Gary Ihas • Yoonseok Lee • Mark Meisel • Neil Sullivan • Yasu Takano • Jian-sheng Xia

  18. FINAL DESIGN

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