Observation of ferromagnetic ordering in conjugated polymers exhibiting OMAR effect

A1 Journal article (refereed)


Internal Authors/Editors


Publication Details

List of Authors: Sayani Majumdar, Jan-Olof Lill, Johan Rajander, Himadri Majumdar
Publisher: ELSEVIER SCIENCE BV
Publication year: 2015
Journal: Organic Electronics
Journal acronym: ORG ELECTRON
Volume number: 21
Start page: 66
End page: 72
Number of pages: 7
ISSN: 1566-1199


Abstract

We report observation of ferromagnetic (FM) ordering in pi-conjugated polymeric semiconductors, namely regio-regular poly (3-hexyl thiophene) (RRP3HT) and 1-(3-methoxycarbonyl)propyl-1-phenyl[6,6]-methanofullerene (PCBM), in the temperature range of 5-300 K. Diodes made from these polymers exhibit sizable magnetoresistance (known commonly as OMAR). However, upon blending these two materials, the FM ordering is suppressed by a huge paramagnetic (PM) signal. In the diodes with RRP3HT:PCBM blend showing PM response, OMAR decreases substantially. Particle induced X-ray emission spectroscopy indicate presence of dilute magnetic impurities as residues from the synthesis process in the individual polymers. However the impurity signal is unable to explain the temperature dependence of magnetization in these materials and the observed paramagnetism of the RRP3HT:PCBM blend. We propose a hypothesis for the origin of the FM nature of these polymers based on ours and previously reported experimental observations and pointed out that the reported organic magnetoresistance might have a close correlation with the ferromagnetic interaction in these polymers. (C) 2015 Elsevier B.V. All rights reserved.


Keywords

Magnetic semiconductor, Organic magnetoresistance, PIXE

Last updated on 2019-25-08 at 06:06