Saparov Bayrammurad, Sefat Athena S
Materials Science & Technology Division, Oak Ridge National Laboratory, P. O. Box 2008, Building 4100, 1 Bethel Valley Road, Oak Ridge, TN 37831-6056, USA.
Dalton Trans. 2014 Oct 28;43(40):14971-5. doi: 10.1039/c4dt01068j. Epub 2014 Jun 5.
The effects of thermal-annealing on the antiferromagnetic (TN) and structural (Ts) transition temperatures of ThCr2Si2-type BaFe2As2 and SrFe2As2 ('122') crystals are reported and compared to that of CaFe2As2. Although the shift in transition temperature for CaFe2As2 can be as high as 75 K, we find modest changes of ∼6 K for BaFe2As2 and SrFe2As2. Such findings are based on the measurements of temperature dependence of electrical resistivity, magnetization, and heat capacity. Residual resistivity ratios show an improvement of crystal quality upon annealing for both BaFe2As2 and SrFe2As2. We confirm the pressure-like influence of annealing on the 122 crystals.
报道了热退火对ThCr2Si2型BaFe2As2和SrFe2As2（“122”）晶体的反铁磁转变温度（TN）和结构转变温度（Ts）的影响，并与CaFe2As2的进行了比较。尽管CaFe2As2的转变温度变化高达75 K，但我们发现BaFe2As2和SrFe2As2的变化幅度适中，约为6 K。这些发现基于对电阻率、磁化强度和热容量随温度变化的测量。剩余电阻率比表明，退火后BaFe2As2和SrFe2As2的晶体质量均有所提高。我们证实了退火对122晶体的类似压力的影响。
