Development of a measurement system of physical properties under multiple extreme conditions utilizing tunnel-diode-oscillator circuit

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K05171
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Condensed matter physics II
• Research Institution: Osaka University
• Principal Investigator: Kida Takanori 大阪大学, 理学研究科, 助教 (50452412)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 多重極限環境 / パルス強磁場 / トンネルダイオード振動法 / 鉄系超伝導体

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.

Free Research Field

強磁場物性