Half-integer quantum fluxoid state in Sr2RuO4 microrings

The ruthenium oxide superconductor Sr2RuO4 is considered to be in the spin triplet equal spin state from nuclear magnetic resonance (NMR) experiments. It is known that fluxoids are quantized in units of magnetic flux quantum Φ0 in superconductors, but in such superconducting states, wavefunctions also have spin degrees of freedom compared to orbital degrees of freedom, so flaxoids There Fai 0 will be possible to quantize / 2 to the unit. Such a flaxoid state is called a half-integer quantum flaxoid, and its observation has been reported from studies of magnetic torque [1].

n our experiments, we have conducted research aiming to detect half-integer quantum fluxoids from magnetic transport properties. For that purpose, we processed the Sr2RuO4 single crystal into a ring shape using a focused ion beam (Fig.) And measured the electrical resistance at the four terminals. Then, we observed the peak splitting of the magnetoresistive oscillation expected in the half-integer quantum flaxoid. See the APS web page for details.This study is a collaborative study with a group of Professor Aarts at Leiden University. There is also a preprint, so please see here as well.

Small ring of Sr2RuO4 .
[1] J. Jang  et al ., Science  331 , 186 (2011).

Article information

Yasui, Y; Lahabi, K; Anwar, M S; Nakamura, Y; Yonezawa, S; Terashima, T; Aarts, J; Maeno, Y

Little-Parks oscillations with half-quantum fluxoid features in Sr2RuO4 microrings Journal Article

In: Physical Review B, vol. 96, no. 18, 2017.

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