TY - JOUR
T1 - Characterization of the resistive transition of MgB2 nanogranular films by current noise analysis
AU - Rajteri, Mauro
AU - Portesi, Chiara
AU - Accardo, Maurizio
AU - Taralli, Emanuele
AU - Monticone, Eugenio
AU - Gandini, Claudio
AU - Masoero, Aldo
AU - Andreoli, Valentina
AU - Mazzetti, Piero
PY - 2009/6
Y1 - 2009/6
N2 - An original model for the interpretation of the noise produced during the resistive transition of disordered granular superconductive films, induced by a slow temperature change, has been recently developed and tested on MgB 2 films. Both the amplitude and frequency behavior of the noise power spectrum, simulated on the basis of this model, are in very good agreement with the experimental data, practically without the introduction of adjustable parameters. The model is based on the onset of correlated transitions of large sets of grains, forming resistive layers through the film cross-section area during the transition process. The strong non-linear behavior and correlation of the grains produces abrupt resistance variations, giving rise to the large noise, of the 1 /f3 type, observed in experiments. Presently this model is tested under more general conditions, producing the resistive transition under an external magnetic field. The results show that the field reduces the grain critical current density but does not change the mechanism of the transition process. An alternative transition model, based on fluxoids depinning and motion, which would produce a much lower, 1/f type transition noise, can thus be excluded by the present analysis.
AB - An original model for the interpretation of the noise produced during the resistive transition of disordered granular superconductive films, induced by a slow temperature change, has been recently developed and tested on MgB 2 films. Both the amplitude and frequency behavior of the noise power spectrum, simulated on the basis of this model, are in very good agreement with the experimental data, practically without the introduction of adjustable parameters. The model is based on the onset of correlated transitions of large sets of grains, forming resistive layers through the film cross-section area during the transition process. The strong non-linear behavior and correlation of the grains produces abrupt resistance variations, giving rise to the large noise, of the 1 /f3 type, observed in experiments. Presently this model is tested under more general conditions, producing the resistive transition under an external magnetic field. The results show that the field reduces the grain critical current density but does not change the mechanism of the transition process. An alternative transition model, based on fluxoids depinning and motion, which would produce a much lower, 1/f type transition noise, can thus be excluded by the present analysis.
KW - Dynamic noise
KW - Magnetic field
KW - Simulation
KW - Superconductive transition
UR - http://www.scopus.com/inward/record.url?scp=68649083936&partnerID=8YFLogxK
U2 - 10.1109/TASC.2009.2018505
DO - 10.1109/TASC.2009.2018505
M3 - Article
SN - 1051-8223
VL - 19
SP - 2827
EP - 2830
JO - IEEE Transactions on Applied Superconductivity
JF - IEEE Transactions on Applied Superconductivity
IS - 3
M1 - 4982604
ER -