The introduction of artificial pinning sites in YBa2 Cu3O7−d (YBCO) epitaxial thin films has been obtained by pulsed laser deposition ͑PLD͒ technique from YBCO-BaZrO3 ͑BZO͒ composite targets with BZO concentration ranging from 2.5 to 7 mol %. The typical critical temperature, Tc , drop observed in YBCO-secondary phase films grown by PLD has been successfully recovered by increasing the deposition temperature. Transport properties analyses revealed improved pinning force values for YBCO-BZO films for BZO concentration above 5 mol %. These films exhibited an anomalous dual peak structure which has been ascribed to the presence of two pinning contributions. The crossover field, Bm , separating these two pinning regimes has been observed to be temperature independent suggesting the occurrence of the matching field effect. The measured value of Bm agreed with the matching field value, B⌽ = Knd⌽0 , as evaluated from transmission electron microscopy investigations. The mark of this phenomenon is retained down to 10 K, making YBCO-BZO more performing than pristine YBCO films at applied magnetic fields below Bm in all the temperature range inspected. On the contrary, in the high magnetic field range ͑above Bm͒, the effectiveness of correlated pinning is progressively reduced on lowering the temperature suggesting that at low temperatures the dominant pinning contribution arises from isotropic pinning centers.

A., A., G., C., V., G., A., M., A., R., A., V., et al. (2010). Pinning analyses on epitaxial YBa2Cu3O7−δ films with BaZrO3 inclusions. JOURNAL OF APPLIED PHYSICS, 108, 063906-1-063906-5 [10.1063/1.3477451].

Pinning analyses on epitaxial YBa2Cu3O7−δ films with BaZrO3 inclusions

POMPEO, NICOLA
2010-01-01

Abstract

The introduction of artificial pinning sites in YBa2 Cu3O7−d (YBCO) epitaxial thin films has been obtained by pulsed laser deposition ͑PLD͒ technique from YBCO-BaZrO3 ͑BZO͒ composite targets with BZO concentration ranging from 2.5 to 7 mol %. The typical critical temperature, Tc , drop observed in YBCO-secondary phase films grown by PLD has been successfully recovered by increasing the deposition temperature. Transport properties analyses revealed improved pinning force values for YBCO-BZO films for BZO concentration above 5 mol %. These films exhibited an anomalous dual peak structure which has been ascribed to the presence of two pinning contributions. The crossover field, Bm , separating these two pinning regimes has been observed to be temperature independent suggesting the occurrence of the matching field effect. The measured value of Bm agreed with the matching field value, B⌽ = Knd⌽0 , as evaluated from transmission electron microscopy investigations. The mark of this phenomenon is retained down to 10 K, making YBCO-BZO more performing than pristine YBCO films at applied magnetic fields below Bm in all the temperature range inspected. On the contrary, in the high magnetic field range ͑above Bm͒, the effectiveness of correlated pinning is progressively reduced on lowering the temperature suggesting that at low temperatures the dominant pinning contribution arises from isotropic pinning centers.
2010
A., A., G., C., V., G., A., M., A., R., A., V., et al. (2010). Pinning analyses on epitaxial YBa2Cu3O7−δ films with BaZrO3 inclusions. JOURNAL OF APPLIED PHYSICS, 108, 063906-1-063906-5 [10.1063/1.3477451].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/119147
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