Spin-triplet superfluids can support exotic objects, such as half-quantum vortices characterized by the nontrivial winding of the spin structure. We present cantilever magnetometry measurements performed on mesoscopic samples of Sr2RuO4, a spin-triplet superconductor. For micron-sized annular-shaped samples, we observe transitions between integer fluxoid states, as well as a regime characterized by "half-integer transitions," i.e., steps in the magnetization with half the height of the ones we observe between integer fluxoid states. These half-height steps are consistent with the existence of half-quantum vortices in superconducting Sr2RuO4.
@article{arxiv.1101.3611,
title = {Observation of half-height magnetization steps in Sr2RuO4},
author = {J. Jang and D. G. Ferguson and V. Vakaryuk and R. Budakian and S. B. Chung and P. M. Goldbart and Y. Maeno},
journal= {arXiv preprint arXiv:1101.3611},
year = {2011}
}