Synthesis of SmFeAsO by an easy and versatile route and its physical property characterization

• Published in: Journal of applied physics 2009-04, Vol.105 (7), p.07E316-07E316-3
• Main Authors: Awana, V. P. S., Pal, Anand, Vajpayee, Arpita, Kishan, H., Alvarez, G. A., Yamaura, K., Takayama-Muromachi, E.
• Format: Article
• Language: English
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.3072382

We report synthesis, structure, electrical transport, and heat capacity of SmFeAsO. The title compound is synthesized by one-step encapsulation of stoichiometric FeAs, Sm, and Sm 2 O 3 in an evacuated ( 10 − 5   Torr ) quartz tube by prolong (72 h) annealing at 1100 ° C . The as-synthesized compound is crystallized in tetragonal structure with P 4 / n m m space group having lattice parameters a = 3.937 26 ( 33 )   A and c = 8.498 02 ( 07 )   A . The resistance ( R - T ) measurements on the compound exhibited ground state spin-density-wave (SDW)-like metallic steps below 140 K. Heat capacity C P ( T ) measurements on the title compound, showed an anomaly at around 140 K, which is reminiscent of the SDW ordering of the compound. At lower temperatures the C P ( T ) shows a clear peak at around 4.5 K. At lower temperature below 20 K, C p ( T ) is also measured under an applied field of 7 T. It is concluded that the C P ( T ) peak at 4.5 K is due to the antiferromagnetic ordering of Sm 3 + spins. These results are in confirmation with ordering of Sm in Sm 2 − x Ce x CuO 4 .