Nuclear Demagnetization Refrigerator

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.

NDR01_2_t NDR01_1_t NDR02_t NDR03_t

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

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

>> page top

Cryogen-Free Dilution Refrigerator

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.

DDR01_t DDR02_t  

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

>> page top

Ultra-Low Temperature Scanning Tunneling Microscope (ULT-STM)

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.

ULT_STM01_t ULT_STM02_e_t  

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


>> page top

Multifunctional ULT Scanning Probe (ULT-STM/AFM/TR)
ULT_SAT01_t ULT_SAT02_t  

Multifunctional ULT scanning probe

The head of new versatile SPM with capabilities of the following measurements:
 ・transport measurements (TR)
on the same sample.
Will be installed in our ULT-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.

>> page top

Lithography facility
lithography01_t lithography02_t lithography03_t

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

Clean booth

>> page top

Film Evaporator
evapolator01_t evapolator02_t  

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

>> page top