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Study on odd frequency Cooper pairs at junction interfaces in tunneling phenomena

Description: In this work, I have studied on odd frequency Cooper pairs at junction interfaces between a ferromagnet and a superconductor. I have clarified several topics as follows:1. I synthesized Heusler alloys Co_<2-x> Fe_xMnSi and Ru_<2-x> Fe_xCrSi, which are expected as half-metal by the first-principles band calculations. Those materials are candidates of half-metal.2. The spin polarization of Co_<2-x> Fe_xMnSi is independent of composition x and is equal to approximately 50%.3. The spin polarization of Ru_<2-x> Fe_xCrSi is maximum value of 63% in the case of x=1. 8.4. I succeed in fabricating fully-epitaxial NbN/Co_2MnSi and NbN/Co_2FeSi bilayers and those nano-junctions in order to trap the odd frequency Cooper pairs.5. I observed a large zero-bias peak in differential conductance of NbN/Co_2MnSi nano-junctions. The phenomenon are not explained by the modified Blonder-Tinkham-Klapwijk(BTK) model and indicates generations of odd frequency pairs at the junction interface.

Funder: Japan Society for the Promotion of Science

Amount: ¥4,420,000

Funding type: fellowship

Funder scheme: Grant-in-Aid for Young Scientists (B)

Investigator: Iduru SHIGETA

Institution: Kagoshima University

Topic: Heusler alloys: electronic and magnetic properties

Subfield: Electronic, Optical and Magnetic Materials

Field: Materials Science

Domain: Physical Sciences

Funded outputs count: 9

Funder award ID: 21740259

OpenAlex ID: G4152017779