14 research outputs found
Critical Currents, Pinning Forces and Irreversibility Fields in (YxTml-x)Ba2Cu3O7 Single Crystals with Columnar Defects in Fields up to 50 T
We have studied the influence of columnar defects, created by heavy-ion (Kr)
irradiation with doses up to 6 10^11 Kr-ions/cm2, on the superconducting
critical parameters of single crystalline (YxTm1-x)Ba2Cu3O7. Magnetisation
measurements in pulsed fields up to 50 T in the temperature range 4.2 - 90 K
revealed that: (i) in fields up to T the critical current Jc(H,T) is
considerably enhanced and (ii) down to temperatures T ~ 40 K the
irreversibility field Hirr(T) is strongly increased. The field range and
magnitude of the Jc(H,T) and Hirr(T) enhancement increase with increasing
irradiation dose. To interpret these observations, an effective matching field
was defined. Moreover, introducing columnar defects also changes the pinning
force fp qualitatively. Due to stronger pinning of flux lines by the amorphous
defects, the superconducting critical parameters largely exceed those
associated with the defect structures in the unirradiated as-grown material:
Jc,irrad(77 K, 5 T) ^3 10* Jc,ref(77 K, 5 T).Comment: 11 pages, all PDF, contribution to Physica
Influence irradiation by high energy heavy ions on piezoelectric, elastic and dielectric properties of ZnO single crystals
C12 (90 MeV) and Ne22 (160 MeV) ion irradiation effects on dielectric, piezoelectric and electromechanical properties of ZnO single crystals have been studied. It was shown that high energy heavy ion irradiation leads to significant changes in electromechanical properties of piezoelectric materials