Production of silicate thin films using pulsed laser deposition (PLD) and applications to studies in mineral kinetics

Abstract

In this paper we describe a setup to efficiently deposit thin films (up to several micrometers) of complex silicate and oxide compositions. We describe the production and characterization of thin films of a variety of natural mineral compositions ( e.g. olivine, garnet, pyroxene and plagioclase solid solutions). The films have been characterized using different techniques ( e.g. RBS, TEM, SEM and white light interference microscopy) and are found to be amorphous, highly uniform (± 1nm) in thickness and of the desired solid solution stoichiometries, as deposited. Small amounts of excess oxygen after deposition can be readjusted by subsequent annealing and such anneals may crystallize the films in some cases ( e.g. several hours at 900°C for olivine). The films have an excellent contact with the substrate even at the HRTEM scale and open the possibility for a variety of studies in mineral kinetic and surface sciences, which are outlined. Some examples of the production of diffusion couples in minerals for measurements that were difficult or impossible before are illustrated. These include Fe-Mg diffusion in olivine at low temperatures, Si and O diffusion in olivine and diffusion of Lu in garnets.