摘要
We measured lifetime and doppler broadening spectra of Sm_(2/3)Sr_(1/3)MnO_(3+δ) as functions of temperature by positron annihilation technology In terms of lifetime spectrum,we found that the lattice effects triggered by ferromagnetic transition give rise to the change of the coefficient of the average linear thermal expansion of Sm_(2/3)Sr_(1/3)MnO_(3+δ) at Tc.In terms of doppler broadening spectrum,we found the delocalization of low-momentum electrons occurs in Sm_(2/3)Sr_(1/3)MnO_(3+δ) at metal-insulator transition temperature.
