Velocity distributions of laser ablated species from a La Ca MnO target

The velocities of laser ablated species in both ground and excited states from a La–Ca–Mn–O target were measured by both time-resolved quadrupole mass spectrometric and time-resolved optical emission spectrometric techniques. The velocity distribution can be fitted by a Maxwell–Boltzmann distribution with a stream velocity and the stream velocity was found to increase with the plume expansion. The velocities estimated from the two techniques differ greatly from each other, which can be explained in the view of the origins of the signals measured by two different techniques. The ablated species is split into two components during expansion in an ambient, and the velocity of each is examined as a function of the laser fluence. q1999 Elsevier Science B.V. All rights reserved.