Structure, magnetization, specific heat, and microwave properties of KxFe2–ySe2. (11th July 2016)

• Record Type: Journal Article
• Authors: Yazici, D; Basaran, Ali C; J G Ramírez, ; Schuller, Ivan K; Maple, M B
• Is Part Of: Superconductor science & technology. Volume 29:Number 8(2016:Aug.)
• Publication Date: 2016-07-11
• Subjects: superconductivity -- microwave properties -- specific heat; 74.25.F- -- 74.25.Dw -- 74.62.Bf; Superconductivity -- Periodicals; Superconductors -- Periodicals; 537.623
• DOI: 10.1088/0953-2048/29/8/085015
• Languages: English
• ISSNs: 0953-2048

Abstract

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.