Thin Films of (Fe1-xCox)(3)P and Fe-3(P1-xTex) from the Co-Decomposition of Organometallic Precursors by MOCVD

摘要

A new method for preparing thin films of ternary transition metal phosphides has been developed. The ferromagnetic compound Fe3P has been doped with cobalt and tellurium by decomposing H2Fe3(CO)(9)(PBu)-Bu-t with either Co-3(CO)(9)(PBu)-Bu-t or H2Fe3(CO)(9)Te via metal-organic chemical vapor deposition (MOCVD) onto a quartz substrate. Solid mixtures of the organometallic clusters were vaporized and decomposed at 400 degrees C to produce films that were subsequently annealed under vacuum at 650 degrees C for 24 h to afford crystalline films of (Fe1-xCox)3(P) (0.09 < x < 0.22) and Fe-3(P1-xTex) (0.04 < x < 0.42). The films exhibit phase purity as confirmed by powder X-ray diffraction and X-ray photoelectron spectroscopy, which also confirmed the homogeneity of the films. Changes in elemental ratios were tracked by unit cell constants and ICP-OES analysis. Field-dependent magnetization measurements showed magnetic hysteresis with similar magnetic saturation values for each doped material. Thermogravimetric analysis was used to compare the Curie temperatures (T-c) of pristine Fe3P (thin film) and the doped films; Co-doping was found to lower the T-c by up to 7 degrees C and Te-doping had no observable effect on the T-c.