| Budget Amount *help |
¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000)
Fiscal Year 2017: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2016: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2015: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
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| Outline of Final Research Achievements |
Radio frequency (rf) techniques are quite useful in transport measurements under high pressure due to the contactless configuration of a compact searching coil and the extremely high sensitivity. In the present study, we have developed a contactless conductivity measurement apparatus utilizing an rf oscillator under high pressure and high magnetic fields. High pressures of up to 6 GPa are generated with a diamond anvil cell (DAC) made of Ni-Cr-Al alloys. Utilizing this apparatus, we measured the frequency change to determine the upper critical fields (Hc2) of Fe(Te,Se). At ambient pressure, Hc2 for H || c of FeTe0.6Se0.4 was almost linear against T near Tc (~ 14 K) and was suppressed at low temperatures compared to the conventional one-band the WHH prediction. Under high pressure, suppression of the Hc2 at low temperatures became more pronounced. However, we found that the effect of the eddy current heating from the gasket cannot be negligible during field descending process.
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