  Recent discovery of superconductivity in iron pnictides had attracted immense
attention of the scientific community. The parent compounds were spin density
wave (SDW) metals unlike the high-TC superconductors which were Mott
insulators. In this present study, we synthesized single crystal of a new
compound YbFe2As2 by using high temperature solution growth technique without
flux. The YbFe2As2 single crystals had been systematically characterized by
energy dispersive X-ray analysis (EDAX). The presence of oxygen was found by
EDAX on the surfaces of grown YbFe2As2 single crystals which had been kept in
air ambience for few months. The measurement of magnetization (M) versus
temperature (T) using SQUID at constant magnetic field (H = 100 Oe) for
YbFe2As2 had revealed an occurrence of sharp slope change around 140 K which
was the known SDW transition temperature for the parent compound BaFe2As2. An
additional slope change had been observed around 40 K. M vs T data at H= 10000
Oe had exhibited paramagnetic behavior. Result of M versus H measurements for
YbFe2As2 at 2 K had shown that the saturation had not been achieved at H =
80000 Oe. We had carried out magnetization measurements for oxygen adsorbed
YbFe2As2 (YbFe2As2 : O2 ) and BaFe2As2 (BaFe2As2 : O2) for comparative study
also.
