Combination of strong natural and artificial pinning centers in Co-doped BaFe2As2 films

B. MAIOROV; T. KATASE; M. WEIGAND; I. USOV; N. HABERKORN; H. HIRAMATSU; H. HOSONO; L. CIVALE

Boston

Congreso; APS March Meeting 2012; 2012

American Physical Society

Studying the angular dependence of the critical current density (Jc) as a function of temperature in superconductors with complex pinning landscapes is very important from technical and fundamental points of view. The low anisotropy found in the BaFe2As2 (Ba122) family together with strong naturally grown pinning make Ba122 films very attractive. We present results on Ba122 superconducting films with naturally grown correlated defects with the addition of different amounts of random defects produced by consecutive irradiations with 3MeV protons. We analyze the changes of Jc, Hirr and Hc2 as a function of field, angle and temperature. Irradiations produce a small decrease in critical temperature (Tc of 0.5 K per 1x10^16 cm^-2 dose. After the irradiation, the pinning near the c-axis remains almost unchanged (except for the effects from the decrease of Tc. On the other hand, an increase of Jc is observed for other field orientations indicating and stronger random pinning contribution, particularly at high fields