Quantum Size Effects on Vanadium Nanoparticles

• Published in: IEEE transactions on magnetics Vol. 47; no. 10; pp. 3535 - 3537
• Main Authors: Yang, Chun-Chuen, Huang, Wei-Luen, Lin, Yi-Hsin, Weng, Chang-Yu, Mo, Zh-Yu, Chen, Yang-Yuan
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.10.2011; Institute of Electrical and Electronics Engineers
• Subjects: Critical diameter; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Kubo gap; Magnetic susceptibility; Materials science; Metals; nano; Nanoparticles; Other topics in materials science; Physics; Solids; Superconducting magnets; superconductivity; X-ray diffraction; Vanadium additions; Nanoparticles; Kubo gap; Size effect; Superconductivity; Vanadium; nano; Critical diameter; Magnetic properties
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2011.2146762

Vanadium nanoparticles of two sizes were fabricated by pulse laser deposition. Transmission electron microscopy (TEM) images revealed that the diameters of the particles two samples were 2.5 and 4 nm. X-ray diffraction was used to determine the purity and lattice constant. Both samples were in the cubic 1-3-m phase. The lattice constants increased with diameter: the 4- and 2.5-nm samples had constants that were 0.42% and 0.55% larger than the lattice constant of the bulk, respectively. Superconductivity behaviors were determined by experiments on magnetic susceptibility. No Meissner effect was observed in the 2.5-nm nanoparticles. The T c of the 4-nm nanoparticles was about 5.4 K, and accompanied a H c of about 500 Oe. The critical diameter of vanadium nanoparticles for superconductivity can be estimated using Kubo theory 1,2 . The calculated critical diameter of the Kubo gap for superconductivity (~ 1.6 meV) is about 3 nm. This fact is believed to be the main explanation of the lack of superconductivity in 2.5-nm nanoparticles.