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Contamination from magnetic starting materials in flux-grown single crystals of RFeAsO superconductors
Physical Review B
  • J.-Q. Yan, Iowa State University
  • Qingfeng Xing, Iowa State University
  • Brandt A. Jensen, Iowa State University
  • H. Xu, Iowa State University
  • Kevin W. Dennis, Iowa State University
  • R. William McCallum, Iowa State University
  • Thomas A. Lograsso, Iowa State University
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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.

This article is from Physical Review B 84 (2011): 012501, doi:10.1103/PhysRevB.84.012501.

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American Physical Society
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J.-Q. Yan, Qingfeng Xing, Brandt A. Jensen, H. Xu, et al.. "Contamination from magnetic starting materials in flux-grown single crystals of RFeAsO superconductors" Physical Review B Vol. 84 Iss. 16 (2011) p. 012501
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