Flux pinning properties of correlated pinning at low temperatures in ErBCO films with inclined columnar defects

Awaji, Satoshi*; Namba, Masashi*; Watanabe, Kazuo*; Kai, Hideki*; Mukaida, Masashi*; Okayasu, Satoru  

The effect of -axis correlated pinning on the critical current density at low temperatures under high magnetic fields was investigated on the basis of the transport measurements of and irreversibility field B properties of an ErBaCuO film with inclined columnar defects. The contribution of correlated pinning on decreased drastically with decreasing temperature under high magnetic fields above the matching field. At low temperatures, the presence of a matching field limited the pinning force for correlated pinning, while the ratio of the maximum pinning force of the correlated pinning to the random one was proportional to the inverse of B. In order to improve the critical current properties at low temperatures under high magnetic fields, an increase in the matching field and/or the introduction of strong random pinning are effective.