Journal or Book Title
Physical Review B
While the flux growth often provides the best method for obtaining single crystals of new-novel materials, the process is prone to producing crystals with trapped second-phase inclusions. In the case of NdFeAsO single crystals grown out of NaAs flux under ambient pressure, some crystals show a lambda anomaly in the specific heat curve at ~12 K. This anomaly is missing in other crystals from the same batch. We show that the lambda anomaly at 12 K is from residual NdAs starting material which is mainly on the edges of the crystals. The isothermal magnetization of LaFeAsO at 300 K clearly illustrates the effect of ferromagnetic impurities on the magnetic properties of LaFeAsO crystals.
American Physical Society
Yan, J.-Q.; Xing, Qingfeng; Jensen, Brandt A.; Xu, H.; Dennis, Kevin W.; McCallum, R. William; and Lograsso, Thomas A., "Contamination from magnetic starting materials in flux-grown single crystals of RFeAsO superconductors" (2011). Ames Laboratory Publications. 54.