Hwang, Inrok Lee, Keundong Jin, Hyunwoo Choi, Sunhwa Jung, Eunok Park, Bae Ho Lee, Suyoun 2024-01-20T07:03:51Z 2024-01-20T07:03:51Z 2021-09-05 2015-05 2040-3364 https://pubs.kist.re.kr/handle/201004/125497 Point contact Andreev reflection (PCAR) has become a standard method for measuring the spin polarization (P) of spintronic materials due to its unique simplicity and the firm physical ground, but it is still challenging to achieve a clean point contact between a superconductor (SC) and a metal (N) for implementing PCAR. In this work, we suggest a much simpler method for PCAR measurement, where a point contact between SC and N is provided by a metallic filament in a transition-metal oxide generated by electrical bias. This method has been successfully demonstrated using a structure composed of Nb/NiO/Pt, where P of the Ni filament was estimated to be about 40%, consistent with the known value of the bulk Ni. In addition, we investigated the dependence of the conductance spectrum on the measurement temperature and the magnetic field. We found that the superconductivity is not fully suppressed until 9 T far above the critical field of Nb, which is associated with the nm-sized constriction of our SC/N junction, much smaller than the coherence length of the SC. English ROYAL SOC CHEMISTRY ENERGY-GAP STRUCTURE UPPER CRITICAL-FIELD SPIN-POLARIZATION FILMS SUPERCONDUCTORS EXPLANATION RESISTANCE NIOBIUM FE NI A new simple method for point contact Andreev reflection (PCAR) using a self-aligned atomic filament in transition-metal oxides Article 10.1039/c4nr07262f 1 NANOSCALE, v.7, no.18, pp.8531 - 8535 NANOSCALE 7 18 8531 8535 scie scopus 000354044600037 2-s2.0-84928923378 Chemistry, Multidisciplinary Nanoscience & Nanotechnology Materials Science, Multidisciplinary Physics, Applied Chemistry Science & Technology - Other Topics Materials Science Physics Article ENERGY-GAP STRUCTURE UPPER CRITICAL-FIELD SPIN-POLARIZATION FILMS SUPERCONDUCTORS EXPLANATION RESISTANCE NIOBIUM FE NI