Irreversibility lines of EuBa2Cu3O7−δ films bombarded by 230 MeV Au14+ ions criterion dependence

Abstract We have investigated the effect of columnar defects on the irreversibility line of 500 nm thick EuBaCuO films. The irradiation dose D of 230 MeV Au 14+ ions is chosen as 2.3 × 10 15 , 4.0 × 10 15 , 6.0 × 10 15 and 8.0 × 10 15 ions/m 2 . Both the critical temperature and the irreversibility line are affected systematically as D increases. The AC magnetic field has an amplitude μ 0 H AC of 0.1 mT and a frequency of 1 kHz while the DC magnetic field varies from 10 −4 to 1 T to track the irreversibility line under the identical criterion. We also compare the irreversibility line obtained by means of harmonic susceptibility with that determined from a pinch point in the M − H hysteresis curve, but they are not continuous to each other. It is found that the irreversibility line is strongly dependent on the J c criterion.