Angela NIGRO Curriculum

Angela Nigro-Laurea in Physics, (110/110 e lode), University of Salerno, (1987), Present PositionAssociate Professor in Physics, Physics Department “E. R. Caianiello”, University of Salerno.The scientific activity has been focused on realization and characterization of thin films of superconducting materials and on tunnel and Josephson devices based on superconducting electrodes. The superconducting and normal properties of Nb, NbN, NbxTi1-x, (NbxTi1-x)N has been investigated for possible applications in High Energy Physics (as coating materials in rf cavities for high energy accelerators and as particle detectors) and for applications in superconducting electronic devices. High quality NbN-NbOx-Pb Josephson devices have been fabricated. The junction microwave quality factor Q and other a.c. properties has been determined via measurements of the amplitude of Fiske resonant modes in the junctions at different resonant frequencies. Theoretical analysis of the results shows that the main contribution to the losses is related to the surface impedance of the electrodes.Thin films of NbN, NbxTi1-x were prepared by reactive sputtering using a d.c. magnetron, high rate, triode type, sputtering gun. The structural (lattice parameters) and transport properties ( resistivity as a function of temperature, critical temperature and magnetic penetration depth) of the films were studied as a function of the realization condition ( nitrogen partial pressure and substrate temperature). The easiness of production by reactive sputtering also on relatively cold surfaces, the low sensitivity to radiation damage and the excellent superconducting properties have make these materials very attractive for superconducting thin film coatings in r.f. cavities for high energy accelerators.Research on high Tc materials (ReBCO, BISCCO and NCCO) were also carried out on bulk and thin film samples. A great deal of effort was devoted to building up sputtering deposition systems for the realization of high Tc thin films and multilayer structures.High quality tunnel junctions based on high Tc superconductors were realized. A systematic analysis of the differential conductance curve of tunnel junctions based on high Tc materials was carried out in order to obtain information on the quasiparticle density of states and on the mechanism responsible for superconductivity in these materials and for possible applications in electronic devices.