Intermittent superconductivity in mesoscopic thin-film rings

► We give that the phase diagrams of intermittent superconductivity and of the critical fields. ► The superconducting critical field shows quantum size effect when the ring is small. ► The field is irrelevant to the inner radius when it is much larger than the arm width of the ring. ► The intermittent superconductivity can be tuned by the surrounding medium, which is useful for designing SQUID-type devices.