Disorder and vortex matching effects in nanoperforated ultrathin TiN films

• Published in: Physica. C, Superconductivity Superconductivity, 2010-12, Vol.470, p.S808-S809
• Main Authors: Mironov, A.Yu, Baturina, T.I., Vinokur, V.M., Postolova, S.V., Kropotin, P.N., Baklanov, M.R., Nasimov, D.A., Latyshev, A.V.
• Format: Article
• Language: English
• Subjects: Josephson junction arrays; Nanoscale systems; Superconducting films
• ISSN: 0921-4534; 1873-2143
• DOI: 10.1016/j.physc.2009.12.057

We present the results of the comparative study of low-temperature transport properties of critically disordered nanoperforated titanium nitride films of the thickness less than the superconducting coherence length, ξd. The samples were patterned by the electron beam lithography and the subsequent plasma etching to form a square array of holes, with the hole diameter being ⩾2ξd and the center to center separation being 80nm. In the wide temperature region below the superconducting critical temperature, Tc, we observe a periodic dependence of the resistance upon the external magnetic field, with the period corresponding to the magnetic flux quantum per unit cell. On top of that we see secondary minima at the half-integer quanta points. We find that the effect of perforation on the low-temperature (⩽0.1Tc) magnetoresistance depends drastically on the degree of disorder. Namely, in the moderately disordered films (kFl≃3) the perforation results in the shift of magnetoresistance curves towards higher fields as compared to those of the original films, while in the more disordered films (kFl≃1), the perforation gives rise to the shift of the magnetoresistance in the opposite direction.