IRREVERSIBILITY LINES OF EUBA2CU3O7-DELTA FILMS BOMBARDED BY 230 MEV AU(14- CRITERION DEPENDENCE() IONS )

We have investigated the effect of columnar defects on the irreversibi lity line of 500 nm thick Eu-Ba-Cu-O films. The irradiation dose D of 230 MeV Au14+ ions is chosen as 2.3 x 10(15), 4.0 x 10(15), 6.0 x 10(1 5) and 8.0 x 10(15) ions/m(2). Both the critical temperature and the i rreversibility line are affected systematically as D increases. The AC magnetic field has an amplitude mu(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 trac k the irreversibility line under the identical criterion. We also comp are the irreversibility line obtained by means of harmonic susceptibil ity with that determined from a pinch point in the M-H hysteresis curv e, but they are not continuous to each other. It is found that the irr eversibility line is strongly dependent on the J(c) criterion.