Volume 31 Issue 9 - May 31, 2019 PDF
Theoretical prediction of a giant anisotropic magnetoresistance in carbon nanoscrolls
Ching Hao Chang1,2,* and Carmine Ortix3
1 Department of Physics, National Cheng Kung University
2 Institute for Theoretical Solid State Physics, IFW Dresden, Germany
3 Institute for Theoretical Physics, Center for Extreme Matter and Emergent Phenomena, Utrecht University, Netherlands
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【107 MOE Yushan Young Scholars Program】Special Issue

Anisotropic magnetoresistance (AMR) phenomenon has triggered great interest since the development of AMR sensors for magnetic recording. In classical iron, cobalt and nickel alloys this effect originates from an anisotropy in electron scattering due to spin-orbit interaction (SOI). Although the AMR effect has found many applications in magnetic recording and sensor devices, its magnitude lies in the 1% range for typical transition metals and their alloys.
In this work, we investigate for the first time the semiclassical magnetoresistance of carbon nanotubes (see Fig.1), and then predict the occurrence of an AMR effect with a similar magnitude (~80% ) in carbon nanoscrolls (CNS) subject to moderate externally applied transversal magnetic fields. This phenomenon originates from the curved open geometry of rolled-up nanotubes, which leads to a tunability of the number of quasi-one-dimensional magnetic states, and therefore does neither require the presence of magnetism nor the presence of a spin-orbit interaction.

Winning testimonials:I am honored to receive the grant for the Yushan Youth Scholar this year and return to the National Cheng Kung University to teach. I am very grateful to the help of the unversity and the assistance and experience sharing of my colleagues in the department. I am especially grateful to the Ministry of Education and the jury for giving me such a valuable opportunity. I will try my best to contribute in teaching and research, and to give back to Taiwan and National Cheng Kung University.

Figure 1: Magnetoresistance of a carbon nanotube. The x axis is the rate of increase of resistance, the y axis is proportional to the field magnitude.
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