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Observation of a superparamagnetic breakdown in gadolinium chloride filled double-walled carbon nanotubes

Ncube, Siphephile and Coleman, Christopher and Flahaut, Emmanuel and Bhattacharyya, Somnath and Prinsloo, Aletta R. E. and Sheppard, Charles Observation of a superparamagnetic breakdown in gadolinium chloride filled double-walled carbon nanotubes. (2021) AIP Advances, 11 (3). 035206. ISSN 2158-3226

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Official URL: https://doi.org/10.1063/9.0000128

Abstract

In this article, the magnetic properties of gadolinium chloride-filled double-walled carbon nanotubes (GdCl3@DWNTs) in the temperature range 2-300 K are explored. The temperature-dependent phonon frequencies of the G-band were studied from 80-300 K to investigate the effect of temperature on the magnetic ordering. Temperature-dependent susceptibility measurements show that the GdCl3@DWNTs sample has a pronounced superparamagnetic phase from 83 K. The temperature dependence of the G-band frequency for filled tubes exhibited a distinct difference compared to pristine nanotubes, where a sharp phonon hardening at low temperatures was observed. A correlation between the onset temperature of superparamagnetism and the abrupt G-band phonon hardening in the filled tubes was verified. GdCl3@DWNTs were characterized by a finite remnant magnetization at 300 K which decreased as the temperature was lowered because of the presence of the discontinuous magnetic nanoparticles, providing a superparamagnetic contribution characterized by an S-shaped non-saturating hysteresis loop at 2 K. Remarkably, the onset of superparamagnetism, marked by the bifurcation point, occurred at roughly the same temperature where the G-band phonon frequency showed a pronounced hardening at approximately 80 K, indicating a close correlation between phonon modes and spin clusters.

Item Type:Article
Additional Information:All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) li
HAL Id:hal-03164783
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
Other partners > University of Johannesburg - UJ (SOUTH AFRICA)
Other partners > University of the Witwatersrand - WITS (SOUTH AFRICA)
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Deposited On:10 Mar 2021 09:52

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