L. E. Cross

The characterization of films deposited by chemical reaction on ferroelectric-ferroelastic gadolinium molybdate surfaces☆

Abstract X-ray diffraction, ion beam spectrochemical analysis, Auger electron spectroscopy and ion surface scattering techniques were used to characterize the chemically reacted film of gadolinium fluoride on the c surfaces of ferroelectric-ferroelastic gadolinium molybdate single crystals. Composition cersus depth profiles were obtained to determine the nature of the film and film-substrate interface. The ion beam spectrochemical analysis profile of hydrogen suggested a diffusion-controlled mechanism of film growth.

R.F. sputtering of Sr2Nb2O7

Abstract The deposition of Sr2Nb2O7 thin films by conventional r.f. sputtering has been shown to give rise to films with stoichiometry different from that of the target material. The composition offset was traced to an anomalously high resputtering rate from the substrate which occurs for argon, argonoxygen or pure oxygen carrier gases. By suitably adjusting target composition at a fixed sputtering geometry and power level, stoichiometric films were produced. For films deposited onto substrates at temperatures of up to 1100 °C the Sr2Nb2O7 was X-ray amorphous and showed simple linear dielectric properties with no evidence of the ferroelectricity of the corresponding crystalline form. High temperature annealing disrupted the integrity of the film before the crystalline form could be clearly identified.

Investigation of BaTiO3 and Gd2(MoO4)3 crystal surfaces by complementary AES and ISS techniques

Abstract The chemical nature of the intrinsic surface layer in BaTiO 3 single crystals and the positive and negative surfaces of gadolinium molybdate have been determined using AES and ISS. Potassium and fluorine were detected in BaTiO 3 crystals grown by the Remeika method. The ratio of the AES 417 eV to 411 eV peaks of Ti in BaTiO 3 was stable under ion and electron beam irradiation. ISS showed that the positive and negative surface of gadolinium molybdate crystals were chemically identical, with both types exhibiting similar variations in the Gd and Mo signals with ion bombardment time. However, marked differences in the spectra of sputtered and scattered ions from each type were observed.