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https://doi.org/10.3938/NPSM.68.284
Analysis of the Superconducting Characteristics of Niobium Thin Films Deposited by Using a DC Magnetron Sputtering System
New Phys.: Sae Mulli 2018; 68: 284~289
Published online March 30, 2018;  https://doi.org/10.3938/NPSM.68.284
© 2018 New Physics: Sae Mulli.

Joonyoung CHOI1, Jaehyun LEE1, Chang-Duk KIM*1, Younjung JO†1, Jeonghun KANG2, Sung Ho BAE2, Jaehyeok YANG2, Dabin JEONG2

1 Department of Physics, Kyungpook National University, Daegu 41566, Korea
2 Daegu Science High School, Daegu 42110, Korea
Correspondence to: *duks@knu.ac.kr, †jophy@knu.ac.kr
Received December 15, 2017; Revised February 5, 2018; Accepted February 6, 2018.
cc This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
The superconducting characteristics of Nb thin films deposited by using a DC magnetron sputtering system are investigated as a function of the sputtering temperature. The crystallinities of Nb and NbO are analyzed using an X-ray diffractometer (XRD), and the surface characteristics are analyzed using a field-emission scanning electron microscope (FE-SEM) and an atomic force microscope (AFM). The superconducting characteristics of the fabricated Nb thin films are confirmed using measurements of the resistance as a function of the temperature. The Nb thin film grown at a sputtering temperature of 240 $^\circ$C exhibits the highest crystallinity of Nb and the lowest crystallinity of NbO. The superconducting transition temperature ($T_c$) of the optimized film is 8.34 K, which is close to $T_c$ of bulk Nb, 9.25 K. Therefore, we confirm that NbO crystallinity caused by oxygen is the critical factor that inhibits the superconducting characteristics of the Nb thin films.
PACS numbers: 74.25.-q, 81.15.Cd, 74.78.-w
Keywords: Superconducting properties, Deposition by sputtering, Superconducting films


March 2018, 68 (3)
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