Effect of half-quantum vortices on magnetoresistance of perforated superconducting films.

Recent cantilever magnetometry measurements of annular micron-size samples of Sr2RuO4 have revealed evidence for the existence of half-quantum vortices (HQVs) in this material [J. Jang et al., Science 331, 186 (2011)]. We propose to look for HQVs in transport measurements and calculate magnetoresistance of a perforated superconducting film close to the transition temperature in the presence of HQVs. We analyze the dependence of magnetoresistance on the thermodynamic stability of HQVs which, according to Jang et al., can be varied by the application of an in-plane magnetic field and point out features which may help to identify them.