Antiferromagnetic transition inEuFe2As2: A possible parent compound for superconductors

Abstract

Ternary iron arsenide ${\text{EuFe}}_{2}{\text{As}}_{2}$ with ${\text{ThCr}}_{2}{\text{Si}}_{2}$-type structure has been studied by magnetic susceptibility, resistivity, thermopower, Hall, and specific-heat measurements. The compound undergoes two magnetic phase transitions at about 200 and 20 K, respectively. The former was found to be accompanied with a slight drop in magnetic susceptibility (after subtracting the Curie-Weiss paramagnetic contribution), a rapid decrease in resistivity, a large jump in thermopower, and a sharp peak in specific heat with decreasing temperature, all of which point to a spin-density-wave-like antiferromagnetic transition. The latter was proposed to be associated with an $A$-type antiferromagnetic ordering of ${\text{Eu}}^{2+}$ moments. Comparing with the physical properties of the isostructural compounds ${\text{BaFe}}_{2}{\text{As}}_{2}$ and ${\text{SrFe}}_{2}{\text{As}}_{2}$, we expect that superconductivity could be induced in ${\text{EuFe}}_{2}{\text{As}}_{2}$ through appropriate doping.