[12a-S302-8~11] 10.4 半導体スピントロニクス・超伝導・強相関

[12a-S302-8] CoFeBの熱処理による超伝導臨界電流の巨大変調

〇小森 祥央^1,2、Juliet Thompson²、Jason Robinson² (1.名大院理、2.ケンブリッジ大学物質科学)

キーワード：スピントロニクス、超伝導、ジョセフソン接合

The electrical and structural properties of Co₄₀Fe₄₀B₂₀ (CoFeB) alloy are tunable with thermal annealing. This is key in the optimization of CoFeB-based spintronic devices, where the advantageously low magnetic coercivity, high spin polarization, and controllable magnetocrystalline anisotropy are utilised. So far, there has been no report on superconducting devices based on CoFeB. Here, we present our recent experiments on Nb/CoFeB/Nb Josephson devices and demonstrate an enhancement of the critical current by up to 700% following thermal annealing due to increased structural ordering of the CoFeB. Thermal annealing optimization of Josephson coupling across CoFeB demonstrated in this work is an absolutely new concept in the field of superconducting spintronics and hence the results are the key towards the development of superconducting spintronic devices in which tunable attractive properties of CoFeB are utilized.