Journal or Book Title
Applied Physics Letters
Millimeter-sized LaFeAsO single crystals have been successfully grown out of NaAs flux starting with (LaAs+1/2Fe2O3):20NaAs. The factors which allow the growth of these crystals out of NaAs but not out of many other fluxes, such as FeAs, have been investigated. X-ray powder diffraction found that NaAs synthesized for the growth ofRFeAsO superconductors has monoclinic LiAs structure. Thermal analysis confirmed that NaAs melts congruently at about 600 °C. The ability to extract RFeAsO crystals from this NaAs flux suggests that NaAs has a significant oxygen solubility, possibly due to the formation of the ternary compound NaAsO2, and enough oxygen diffusivity to transport solute to the growth front. Oxygen solubility and diffusivity are two important factors in searching for an alternative environmentally benign flux for the growth of RFeAsOsuperconductors.
Copyright 2011 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
American Institute of Physics
Yan, J.-Q.; Jensen, Brandt A.; Dennis, Kevin W.; McCallum, R. William; and Lograsso, Thomas A., "Flux requirements for the growth of RFeAsO (R = rare earth) superconductors" (2011). Ames Laboratory Publications. 121.