Colossal terahertz magnetoresistance at room temperature in epitaxial La<sub>0.7</sub>Sr<sub>0.3</sub>MnO<sub>3</sub> nanocomposites and single-phase thin films [electronic resource].
- Washington, D.C. : United States. Dept. of Energy, 2017. and Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
- Physical Description:
- 2,506-2,511 : digital, PDF file
- Additional Creators:
- Los Alamos National Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
- Restrictions on Access:
- Free-to-read Unrestricted online access
- Colossal magnetoresistance (CMR) is demonstrated at terahertz (THz) frequencies by using terahertz time-domain magnetospectroscopy to examine vertically aligned nanocomposites (VANs) and planar thin films of La<sub>0.7</sub>Sr<sub>0.3</sub>MnO<sub>3</sub>. At the Curie temperature (room temperature), the THz conductivity of the VAN was dramatically enhanced by over 2 orders of magnitude under the application of a magnetic field with a non-Drude THz conductivity that increased with frequency. The direct current (dc) CMR of the VAN is controlled by extrinsic magnetotransport mechanisms such as spin-polarized tunneling between nanograins. In contrast, we find that THz CMR is dominated by intrinsic, intragrain transport: the mean free path was smaller than the nanocolumn size, and the planar thin-film exhibited similar THz CMR to the VAN. Surprisingly, the observed colossal THz magnetoresistance suggests that the magnetoresistance can be large for alternating current motion on nanometer length scales, even when the magnetoresistance is negligible on the macroscopic length scales probed by dc transport. This suggests that colossal magnetoresistance at THz frequencies may find use in nanoelectronics and in THz optical components controlled by magnetic fields. As a result, the VAN can be scaled in thickness while retaining a high structural quality and offers a larger THz CMR at room temperature than the planar film.
- Published through SciTech Connect., 03/13/2017., "la-ur-17-22535", Nano Letters 17 4 ISSN 1530-6984 AM, and James Lloyd-Hughes; C. D. W. Mosley; S. P. P. Jones; M. R. Lees; Aiping Chen; Quan Xi Jia; E. -M. Choi; J. L. MacManus-Driscoll.
- Funding Information:
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