2023-12-19 アルゴンヌ国立研究所(ANL)
◆この超伝導材料は外部刺激に非常に敏感であり、超伝導特性を意のままに強化または抑制できるため、エネルギー効率の高い切り替え可能な超伝導回路の実現が期待されます。従来の半導体トランジスタに代わる産業用の新しいエネルギー効率向上材料として注目されています。
＜関連情報＞
- https://www.anl.gov/article/scientists-reveal-superconductor-with-onoff-switches
- https://www.science.org/doi/10.1126/sciadv.adj5200
ひずみスイッチ可能な磁場誘起超伝導を発見 Strain-switchable field-induced superconductivity
Joshua J. Sanchez,Gilberto Fabbris,Yongseong Choi,Jonathan M. DeStefano,Elliott Rosenberg,Yue Shi,Paul Malinowski,Yina Huang,Igor I. Mazin,Jong-Woo Kim,Jiun-Haw Chu,and Philip J. Ryan
Science Advances Published:24 Nov 2023
DOI:https://doi.org/10.1126/sciadv.adj5200
Abstract
Field-induced superconductivity is a rare phenomenon where an applied magnetic field enhances or induces superconductivity. Here, we use applied stress as a control switch between a field-tunable superconducting state and a robust non–field-tunable state. This marks the first demonstration of a strain-tunable superconducting spin valve with infinite magnetoresistance. We combine tunable uniaxial stress and applied magnetic field on the ferromagnetic superconductor Eu(Fe0.88Co0.12)2As2 to shift the field-induced zero-resistance temperature between 4 K and a record-high value of 10 K. We use x-ray diffraction and spectroscopy measurements under stress and field to reveal that strain tuning of the nematic order and field tuning of the ferromagnetism act as independent control parameters of the superconductivity. Combining comprehensive measurements with DFT calculations, we propose that field-induced superconductivity arises from a novel mechanism, namely, the uniquely dominant effect of the Eu dipolar field when the exchange field splitting is nearly zero.
