Pal, A. and Rani, P. and Hafiz, A. K. and Rao, Ashok and Awana, V. P. S. (2019) Investigation of fundamental and higher harmonic AC magnetic susceptibility of FeSe0.5Te0.5 superconductor. Materials Research Express, 6 (9). 096004- 096014. ISSN 2053-1591

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Abstract

We present the complex harmonic magnetic susceptibilities chi(n) =chi'(n)-i chi ''(n) (n = 1, 3) of FeSe0.5Te0.5 polycrystalline superconducting sample. The ac magnetic susceptibility is measured as a function of various external perturbations such as temperature T, the ac magnetic field amplitude H-ac, frequency v, and the magnitude of dc bias field H-dc. The in-phase (chi'(n)) and out of phase (chi ''(n)) components of the fundamental and third harmonics of ac susceptibility are found to vary as a function of ac driven field. Particularly, the curves shift toward lower temperatures with increasing H-ac. Contrary to ac magnetic field (H-ac), no noticeable change has been observed within the range of applied dc magnetic field (H-dc) of up to 20 Oe. At a fixed ac magnetic field of H-ac = 0.5 Oe, both parts of the third harmonics show frequency dependence. The imaginary part of the third harmonics, chi ''(3) shows a small peak followed by a negative minimum at lower temperatures. The small peak diminishes as the frequency increases. The negative minimum suppresses and shifts towards the higher temperatures as we increase the frequency. To better understand the ac magnetic response under the influence of various perturbations, we have analyzed the polar plots (Cole-Cole) of the complex ac susceptibility for both the harmonics. Our analysis suggests that the studied sample is in a vortex glass state, characterized by a collective flux creep with in Bean's model, while the Kim-Anderson model is ruled out.

Item Type:	Article
Additional Information:	Copyright for this article belongs to M/s IOP Publishing.
Subjects:	Materials Science
Divisions:	UNSPECIFIED
Depositing User:	Mr. Yogesh Joshi
Date Deposited:	19 Aug 2026 11:23
Last Modified:	19 Aug 2026 11:23
URI:	https://npl.csircentral.net/id/eprint/4265

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