We report the experimental observation of half-integer Shapiro steps in the strong ferromagnetic Josephson junction (Nb-NiFe-Nb) by investigating the current-phase relation under radiofrequency microwave excitation. The half-integer Shapiro steps are robust in a wide temperature range from T = 4 to 7 K. The half-integer Shapiro steps could be attributed to co-existence of 0- and pi-states in the strong ferromagnetic NiFe Josephson junctions with the spatial variation of the2 NiFe thickness. This scenario is also supported by the high-resolution transmission electron microscopy characterization of the Nb/NiFe/Nb junction.
Cite
@article{arxiv.2109.13181,
title = {Half-integer Shapiro Steps in Strong Ferromagnetic Josephson Junctions},
author = {Yunyan Yao and Ranran Cai and See-Hun Yang and Wenyu Xing and Yang Ma and Michiyasu Mori and Yuan Ji and Sadamichi Maekawa and Xin-Cheng Xie and Wei Han},
journal= {arXiv preprint arXiv:2109.13181},
year = {2021}
}