Characterisation of ionic species generated during ablation of Bi2Sr2Ca2Cu3O10 by frequency-doubled Nd:YAG laser irradiation

The kinetic energy distribution and mass composition of ions produced during pulsed laser deposition (532 nm Nd:YAG) of the high-Tc superconductor, Bi2Sr2Ca2Cu3O10 (TCzero = 110 K), have been investigated. Ions were detected using a combined cylindrical mirror analyser and quadrupole mass spectrometer. Several different ablation regimes which give rise to energetic ions are readily identified. The low fluence regime at near-threshold energies (< 1 J cm−2) produces photoejected ions between 0 and 20 eV. At higher laser fluences, ions with energies of up to 300 eV are detected. In addition, intriguing effects have been observed for the behaviour of energetic ions in an inert gas ambient (pAr = 10−2 mbar). As well as the expected loss of energy associated with collisional losses, a process which may be an ion-neutral charge exchange mechanism gives rise to discrete peaks with a near-Maxwell-Boltzmann distribution at less than 10 eV.