Gilardi, R.Streule, S.Hiess, A.Ronnow, H. M.Oda, M.Momono, N.Ido, M.Mesot, J.2007-01-242007-01-242007-01-24200410.1016/j.physb.2004.03.257https://infoscience.epfl.ch/handle/20.500.14299/239945We present an inelastic neutron scattering study of the spin dynamics in the mixed phase of the high-T-c superconductor La2-xSrxCuO4, In the overdoped regime (x = 0. 17, T-c = 37 K) the application of a magnetic field induces a spectral weight redistribution centered around the zero-field spin gap (Delta(SG) approximate to 5 6.5 meV). Moreover the opening of the spin gap seems to track the irreversibility temperature (related to the melting of the vortex lattice) rather than T-c, indicating an unusual interplay between the mesoscopic and microscopic properties in La2-xSrxCuO4. In the underdoped regime (x = 0. 10, T-c = 29 K) our zero-field data indicate a strong decrease (or even vanishing) of the spin gap in the superconducting state and no dependence upon the application of a magnetic field.high-Tsuperconductorspin excitationsmagnetic fieldHIGH-TEMPERATURE SUPERCONDUCTORNEUTRON-SCATTERINGFLUCTUATIONSVORTICESORDERGAPtext::journal::journal article::research article