화학공학소재연구정보센터
Thin Solid Films, Vol.317, No.1-2, 285-289, 1998
Magnetic vortices and pinning in thin films and superlattices
Thin films and superlattices of high-temperature superconductors (HTS) of the 1:2:3 family are grown by de magnetron sputtering with different textures. The samples could be grown with the CuO2 planes parallel to the substrate (the so-called c-axis orientation) or with the CuO2 planes perpendicular to the substrate (the so-called a-axis orientation). The films are superconducting with critical temperatures (T-c) between 85-90 K and with critical currents (J(c)) at 77 K in the range of 10(6) A/cm(2) and 10(5) A/cm(2) for c-axis and a-axis oriented films, respectively. In the case of superlattices of EuBa2Cu3O7/PrBa2Cu3O7 (EBCO/PBCO, superconducting/insulating), the T-c and J(c) change with the modulation lengths. These HTS films show very peculiar magnetic properties in the mixed state. The magnetic properties are linked to the behavior of a very soft magnetic vortex lattice and, in the a-axis oriented superlattices, to the competition between natural and artificial anisotropies. In this case, an enhancement of the critical current density J(c) could be obtained when the magnetic field is applied parallel to the substrate.