■ Nuclear Demagnetization Refrigerator |
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One of the best performances and most compact nuclear demagnetization refrigerator in the world. This is being used mainly for heat capacity and NMR measurements of monolayer helium systems.
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Nuclear demagnetization refrigerator
・Tmin = 51 μK
・holding time: 2 weeks
(T ≤ 200 μK)
Dilution fridge part
・Tmin = 8 mK (no load)
・cooling power: 400 μW @ 100 mK
Superconducting magnet part
・Bmax = 9 T
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Heat-capacity measurement cell
・0.1 ≤ T ≤ 80 mK
・Bmax = 1.3 T |
NMR measurement cell
・60 μK ≤ T ≤ 1.5 K
・Bmax = 0.2 T |
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■ Cryogen-Free Dilution Refrigerator |
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A new type of dilution refrigerator (DR), a pulse-tube refrigerator with pre-cooling stage instead of liquid He bath. Since there is no IVC (inner vacuum can) for thermal isolation, this DR has a large experimental space with easy optical and mechanical accesses. It cools down to 12 mK within 1.5 day with push-button operation. This is being used for various kinds of measurements of quantum fluids and solids, electronic systems, etc.
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Oxford Instruments Model DR200
・Tmin = 12 mK
・cooling power: 200 μW @ 100 mK
・time for cooling down: 35 h (from R.T. to Tmin)
・fully automated |
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■ Ultra-Low Temperature Scanning Tunneling Microscope (ULT-STM) |
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This is a scanning tunneling microscope (STM) which can be operated at temperatures down to 30 mK, in magnetic fields up to 13 T, and in ultra high vacuum (UHV) down to 10-10 mbar.
Under such extreme conditions, this STM has an atomic spatial resolution and an energy resolutions of 100 µeV. Both sample and tip, which are prepared and evaluated in a UHV chamber, can be exchanged in-situ in UHV. After sample/tip exchange, the microscope can be cooled down to mK regime with in a few hours.
Therefore, with this STM, we can study almost all conducting materials in high yield.
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ULT-STM
・Tmin = 30 mK
・Bmax = 13 T
・P ≤ 1 × 10-8 Pa
Sample preparation/analysis
・Ar-ion sputtering
・annealing: T ≤ 1500℃
・electron beam evaporator
・low energy electron diffraction (LEED)
・low-T cleavage mechanism
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■ Multifunctional ULT Scanning Probe (ULT-STM/AFM/TR) |
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Multifunctional ULT scanning probe
The head of new versatile SPM with capabilities of the following measurements:
・STM
・AFM
・transport measurements (TR)
on the same sample.
Will be installed in our ULT-STM.
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RT-STM
The STM head of the first-generation ULT-STM constructed at Univ. of Tsukuba by our group.
Currently used for test experiments in ambient condition. |
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■ Lithography facility |
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Mask aligner
Mikasa model MA-20 (for photolithography) |
Digital optical microscope
left; Keyence model VN-2450 (× 3000)
right; Nikon stereoscopic microscope |
Spin coater
Mikasa model MS-A100 |
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Clean booth |
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■ Film Evaporator |
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High-vacuum evaporator
・P ≤ 1 × 10-6 Pa
・electron beam evaporator × 2
・resistive heating evaporator × 2 |
Three-zone furnace
・P ≤ 1 × 10-4 Pa
・Tmax = 1500℃
・homogeneous region: 40 cm long |
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