Mössbauer and magnetization studies of A0.8Fe 2-ySe2 (A = K, Rb and K/Tl)

I. Nowik*, I. Felner, M. Zhang, A. F. Wang, X. H. Chen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

57Fe Mössbauer spectroscopy and dc magnetization studies of the magneto-superconducting tetragonal A0.8Fe2-ySe 2 (A = K, Rb and K/Tl, y = 0.2-0.3) materials at temperatures of 5-550K have been performed. Below the superconducting transition, magnetization studies performed under low applied fields (H), on both Rb0.8Fe 2-ySe2 and K0.3Tl0.5Fe 2-ySe2 single crystals, show a positive field-cooled branch known as the paramagnetic-Meissner effect for but not for . This paramagnetic-Meissner effect is attributed to a peculiar isothermal hysteresis loop obtained for . Despite being superconducting, due to the antiferromagnetic nature of the materials, Mössbauer spectroscopy studies exhibit well-defined sextets at low temperatures. The full diagonalization of the hyperfine interaction spin Hamiltonian shows clearly that the iron moments are tilted by ∼ 40°-45° away from the c-axis of the low-temperature tetragonal type structure. Moreover, long-term Mössbauer spectroscopy measurements at elevated temperatures suppress the antiferromagnetic state, and the materials measured after cooling to ambient temperatures exhibit a paramagnetic doublet only; its origin is discussed.

Original languageEnglish
Article number095015
JournalSuperconductor Science and Technology
Volume24
Issue number9
DOIs
StatePublished - Sep 2011

Fingerprint

Dive into the research topics of 'Mössbauer and magnetization studies of A0.8Fe 2-ySe2 (A = K, Rb and K/Tl)'. Together they form a unique fingerprint.

Cite this