X-ray spectroscopy and diffraction experiments by using mini-coils: applications to valence state transitions and frustrated magnets

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$X-ray spectroscopy and diffraction experiments by$ transitions and frustrated magnets H.

1 X-ray spectroscopy and diffraction experiments by using mini-coils: applications to valence state transitions and frustrated magnets H. Nojiri, IMR Tohoku Univ., Sendai Japan

2 1. Introduction High Magnetic Fields 2. Mini coil Contents 3. Diffraction experiments 4. XAS and others 5. Neutron Scattering 6. Summary

3 High Magnetic Field Couple to spin and orbital moment of electron, which control properties of condensed matters Strong Precise Non-Contact Time control soft H E P T Basis of the research of materials Magnetism CMR Superconductivity High-Tc Semiconductor Quantum Hall effect Chemistry Molecular magnet Biology Protein(NMR)

4 High Magnetic Field Generator Easy installation to the quantum beam facilities High applicability to various kinds of measurements (several Beamlines, Spectrometers) Increase opportunities to discover interesting field-induced phenomena Development of Miniature Pulsed Magnet technique

5 Miniature Magnet and Portable Capacitor Bank 50 T 870 mm 30 mm 2.4 kj 2000 V 1.2 mf bore: 3 mm Small Energy Small Space High Magnetic Field

6 Mini coil+portable Capacitor Bank Magnet Split Δ2θ = 60 deg. Δχ = 9 deg. Maximum field33 T Pulse width1 ms Repetition15 minutes Bank 5.6 kj 2000 V, 2800 µf 350 kg 2.4 kj 2000 V, 1200 µf 100 kg

7 ID 3mm AgCu wire 0.7mmOD Limited by heating Solenoid Coil for XAS Coil A 20t 8L 274.2m!(RT), 62µH(RT) B (T) B (T) coila coilb µ V (V) V (V)

8 Out look of experimental port Closed Cycle refrigerator 10 K 23 mm 20 mm Gonio Capacitor bank 23 mm Magnet

9 High Magnetic Field XAS Experiments SPring-8 BL22XU Low Temperature T>2K He flow cryostat (Orange Cryo.) Transmission measurement Powdered sample is brushed onto Scotch tape Detection PIN photo diode 3 cm Time domain measurements Recorded by Digital Storage Oscilloscope

10 X-ray diffraction in Pr 1-x Ca x MnO 3 Metal-insulator transition associated with structural phase transition Pr,Ca Mn O a c b M. Tokunaga et al., Phys. Rev. B57 (1998) 5259

11 0 Experimental results T. Arima G.

12 Valence Fluctuation Found in some rare-earth intermetallic compounds for example, Ce SmS YbInCu 4 YbAgCu 4 EuPd 2 Si 2 EuNi 2 (Si 1-x Ge x ) 2 localized state γ Ce valence fluctuation α Ce B-SmS M-SmS J. M. Lawrence et al., Rep. Prog. Phys. 44 (1981) 1. strong c-f hybridization intermediate valence itinerant f-electron Fermi liquid state non-magnetic state sensitive to (T, P, B)

13 Field Induced Valence Transition YbInCu 4 Yb 3+ Yb 2.9+ T v = 42 K III II J.M. Lawrence et al., PRB55 (1997) I. Felner et al., PRB35 (1987) 6956 K. Yoshimura et al., PRL60 (1988) 851

14 VALENCE STATE TRANSITION a / a YbInCu 4 (220) reflection A 30.3 T 28.8 T a / a B Intensity (counts/10 µs) B K. Yoshimura G ! (deg.) T 26.4 T 25.6 T 24.8 T 23.0 T 20.9 T 18.5 T 16.0 T 13.2 T 10.2 T 7.1 T 3.7 T 0.5 T Integrated Intensity (a.u.) (a) A B (b) 0 M A B (T) JPSJ 75 (2006) M (arb. units)

15 Synchrotron X-ray Absorption Spectroscopy (XAS) Electronic Structure 3d, (4d, 5d) E F Inner shell transition e.g, L 3 transition : 2p 3/2 3d (4d, 5d) Element selective M-I Transition 120 C RT M 2,3 L 3 2p L 2 K M. ABBATE et al., PRB 43 (1991) 7263

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17 High magnetic field electronic state of YbB 12 -log(i/i 0 ) Typical Kondo Semiconductor Valence fluctuation : Yb Valence change at closing of the Kondo gap? YbB K 4.7 K Absorption (arb. units) 5 K kev kev YbB E (kev) 1% E (kev) log(i/i 0 ) B (T) No Change! K 4.7 K E (kev) 8.944

18 Future R&D Detection- Time and Space resolved Low noise Multi-wave length Field Method Longer duration Fast cooling-nitrogen cooling Repetitive Short Pulse(Dynamics) MCD, Resonant, Soft X-ray, Time-resolved

19 60 Various High field devices for Neutron To 100 T 60 T Pulse 15 m T pulse High Tc-S.C. Hybrid HMI 20 Repeating Pulse s. 5 m. Inelastic Continuous Normal S.C t(msec)

20 ND in repeating pulsed magnetic field CuFeO 2 Multi-ferroic for NC structure

Mini Coil for Neutron The Highest Magnetic Field for ND Repating :25T @ KEK (Motokawa

Reactor Facility High Beam Flux Beam Focusing is easier.

21 Mini Coil for Neutron The Highest Magnetic Field for ND Repating KEK (Motokawa et al. 1989) ND over 20T is still Difficult. Reactor Facility High Beam Flux Beam Focusing is easier. Development of Easier and more Diffusive Techniques Target : H=40T Goal: Observation of Magnetic Transitions by ~100 Shots Experiments Development to J-PARC

22 Double Magnet System L 1 ~0.1mH, L 2 ~1mH C=0.96mF (Short Pulse) C=2.8 mf (Long Pulse) Longer Pulse Low loss Effective injection Current limit Design Freedom Magnetic Field 4.5msec

Experimental The Triple Axis Spectrometer,

23 Experimental The Triple Axis Spectrometer, AKANE of Tohoku JRR-3M, JAEA, Japan He Cryostat AKANE The coil & Sample were cooled in a liquid-he cryostat. λ=2.0å Colimation: guide-open-s- Blank-Blank Scattering Plane: a*-c* H//c Sample Space (φ5mm L10mm)

24 Observation of Spin-Flop at 10T Integration of (100) magnetic reflection after 100shots We succeeded in observing intensity change due to SF transition at 10T after 100 shots. Pulse Interval: ~17min. 100 Pulse ~ 25hr.

25 Test for 30 T 0.35cc Single

26 Problems to be solved Long Duration of experiments: ~25hr Higher Beam Flux Resolution Control Coil Optimization, low resistive Cooling efficiency, Nitrogen coil Peak Profiles cannot be observed at the present. PSD system θ ω Practical Experiments

27 Summary Miniature magnets are useful for the quantum beam experiments. Structural study (X-ray Diffraction) Electronic States (X-ray Absorption) Magnetic Structure (Neutron Diffraction) apply to various kinds of interesting materials Combination of Pulsed field and X-ray, neutron opens a new horizon in condensed matter

Time-Resolved and Momentum-Resolved Resonant Soft X-ray Scattering on Strongly Correlated Systems

Time-Resolved and Momentum-Resolved Resonant Soft X-ray Scattering on Strongly Correlated Systems Wei-Sheng Lee Stanford Institute of Material and Energy Science (SIMES) SLAC & Stanford University Collaborators