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Temperature driven structural-memory-effects in carbon nanotubes filled with Fe<sub>3</sub>C nano crystals

Boi, Filippo, Zhang, Xiaotian, Corrias, Anna (2018) Temperature driven structural-memory-effects in carbon nanotubes filled with Fe<sub>3</sub>C nano crystals. Materials Research Express, 5 (2). ISSN 2053-1591. (doi:10.1088/2053-1591/aaa994) (KAR id:65794)

Abstract

We report the observation of novel temperature-driven structural-memory-effects in carbon nanotubes (CNTs) filled with Fe3C nano-crystals. These structural-transitions were measured by means of temperature (T) dependent X-ray diffraction (XRD) in the T-range from 298 K to 12 K. A clear reversible 2theta-shift in the 002-peak of the graphitic-CNTs-walls is found with the decrease of the temperature. As determined by Rietveld refinement, such 2theta-shift translates in a not previously reported decrease in the value of the CNT graphitic c-axis with the decrease of the temperature (from 298 K to 12 K). Also, a clear reversible 2theta-shift in the 031 and 131 diffraction-peaks of Fe3C is observed within the same T-range. Rietveld refinements confirm the existence of such memory-effect and also reveal a gradual decrease of the 010-axis of Fe3C with the decrease of the temperature. These observations imply that the observed structural-memory-effect is a characteristic of CNTs when Fe3C is the encapsulated ferromagnet. The generality of such memory-effects was further confirmed by additional measurements performed on other types of CNTs characterized by continuous Fe3C-filling. XRD measurements in the T-range from 298 K to 673 K revealed also an unusual reversible decrease of the Fe3C-peak intensities with the increase of the temperature. These observations can have important implications on the magnetic data recording applications of these nanostructures by helping in better understanding the unusual temperature-dependent magnetic instabilities of iron-based nano-crystals which have been recently reported in literature&#13; &#13;

Item Type: Article
DOI/Identification number: 10.1088/2053-1591/aaa994
Uncontrolled keywords: Carbon Nanotubes, Fe3C, structural-memory effect, magnetic instability
Subjects: Q Science > QD Chemistry
Divisions: Divisions > Division of Natural Sciences > Physics and Astronomy
Depositing User: Anna Corrias
Date Deposited: 26 Jan 2018 14:23 UTC
Last Modified: 11 Jan 2024 10:38 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/65794 (The current URI for this page, for reference purposes)

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