Our main research interest is investigating anomalous behavior of solids. We are particularly interested in unconventional superconductors with a strong focus on ruthenates, Fe-based superconductors, uranium compounds, and organic superconductors.
We are able to grow high-quality single-crystals using furnaces such as a floating-zone furnace with temperatures up to 2500 Kelvin and various atmospheres up to 10 bar pressure. Samples are characterized by energy-dispersive X-ray spectroscopy using X-ray diffractions, and our crystals are used for collaboration researches with other laboratories all over the world.
The interesting behavior described above emerges only at temperatures much lower than room temperature. In order to investigate properties of these phenomena, we use measurement techniques such as electrical resistivity, magnetic susceptibility, specific heat and nuclear magnetic resonance (NMR), in temperatures of down to 20 milli-Kelvin and in magnetic fields up to 17 Tesla.
Thus, we specialize not only in crystal growth but also in many measurement techniques that cover a wide range of temperature (0.02 - 2500 Kelvin) and magnetic fields (0.1 -170000 gauss). This allows us to study and understand many fascinating phenomena.
We are also active in developing measurement techniques to probe properties of solids more accurately and precisely under extreme conditions.
Upper: Super khanthal furnaces. They reach 1600 °C.
Lower: Muffle furnaces. They reach 1050 °C.
X-ray diffractometer for identification and characterization of samples.
Temperatures (Max. 1200 °C) in three zones can be controlled independently. This is useful for single crystal growth by chemical vapor transport.
This furnace is used when performing isotope exchange. Isotope exchange is achieved by annealing samples while circulating isotope gas in the furnace.
SEM: Scanning Electron Microscope
EDX: Energy Dispersive X-ray spectroscopy
Die bonder is used for making small devices.
This furnace is used for making alloy samples or welding metals.
This is mainly used for single-crystal growth of ruthenates.
This is mainly used for crystal orientation analyses of samples.
Helium 3 refrigerator (Oxford Instruments) reaching as low as 0.3 K.
This consists of three superconducting magnets, and they reach 1 Tesla, 0.2 Tesla, 0.2 Tesla, respectively. We can control the direction of field.
There is a refrigerator in the 11 Tesla magnet (blue cylinder). This system can reach 16 mK + 11 Tesla.
A vector magnet and a dilution refrigerator. This can control the direction of field. This reaches 0.05 K and 5 Tesla.
This reaches 0.3 K and 7 Tesla.
Magnetization measurement instrument with SQUID. This covers from 1.8K to 800K and to 7 Tesla.
We can measure capacitance by inserting this into a helium vessel.
A small Dewar for the nuclear quadrupole resonance (NQR) without a magnet. This is equipped with a N2 jacket, and reaches 1.3 K.
We can measure field-angle dependence by rotating the probe. This is equipped with a N2 jacket and has excellent heat retaining property. We need helium transfer only every ten days.
A Dewar for NQR without a magnet.
We can measure field-angle dependence by rotating the probe. This transverse field magnet (max: 8 Tesla) has high homogeneity of a magnetic field for NMR measurement.
This reaches 15 Tesla with high homogeneity of a field (10ppm/cm3). This is equipped with a N2 jacket, and we need helium transfer only once in a week.
This reaches 15 Tesla normally and 17 Tesla with a pump.
A compact dilution refrigerator for NMR and NQR. This can be used in the above Dewars except for the glass Dewar. This reaches about 60 mK, and the samples are directly immersed into 3He-4He mixture. We have three dilution refrigerators for NMR and NQR, and one of them can be used for pressure measurements.