Nano-contact experiments: Energy flow in nano-region and Single molecule magnet

2015 Fiscal Year Final Research Report

• Project/Area Number: 24540314
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Condensed matter physics I
• Research Institution: University of Tsukuba
• Principal Investigator: Ootuka Youiti 筑波大学, 数理物質系, 教授 (50126009)
• Project Period (FY): 2012-04-01 – 2016-03-31
• Keywords: ナノコンタクト / 温度測定 / 熱緩和 / 超伝導ポイントコンタクト / 非平衡状態 / ナノSQUID / 単分子磁石

Outline of Final Research Achievements

By attaching small resistance thermometers to aluminum mechanically-controllable break junction, we measured temperature rise in the immediate vicinities of the nano-contact due to Joule heating at very low temperatures. At the same time we found an evidence of superconductor-to-insulator transition in the I-V curve of the junction, which means the electron temperature exceeds Tc. The rate of temperature rise to heating is about 50 K/microW, which is two- or three- orders of magnitude larger than the values in similar experiments. The temperature rise was independent of the direction of the current through the junction at low-bias conditions, but in some cases it began to depend when the current increased.

Free Research Field

低温物理学