Structure, magnetization, specific heat, and microwave properties of KxFe2–ySe2. (11th July 2016) - Yazici, D
Abstract: Temperature-dependent magnetization, specific heat, and magnetic field modulated microwave spectroscopy (MFMMS) measurements were performed on single crystals of K x Fe 2 − y Se2 . Magnetization measurements yield a superconducting transition temperature ( T c ) of ∼30 K, with a diamagnetic shielding fraction of nearly 90%. Specific heat measurements revealed a 'jump' at T c, Δ C / T ∣ T c, of about 6.8 ± 1 mJ mol −1 K −2, consistent with bulk superconductivity in K x Fe 2 − y Se2 . Moreover, MFMMS measurements detect the superconductivity of K x Fe 2 − y Se2 with a peak with an onset at T c μ ∼ 28 K, close to the values of T c determined from the magnetization and specific heat measurements. The presence and the shape of the low temperature MFMMS signal could be ascribed to a complex dissipation mechanism and percolative superconductivity.