Magnetic-Competition-Induced Colossal Magnetoresistance in n -Type HgCr2Se4 under High Pressure

J. P. Sun, Y. Y. Jiao, C. J. Yi, S. E. Dissanayake, M. Matsuda, Y. Uwatoko, Y. G. Shi, Y. Q. Li, Z. Fang, J. G. Cheng

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14 Scopus citations

Abstract

The n-type HgCr2Se4 exhibits a sharp semiconductor-to-metal transition (SMT) in resistivity accompanying the ferromagnetic order at TC=106 K. Here, we investigate the effects of pressure and magnetic field on the concomitant SMT and ferromagnetic order by measuring resistivity, dc and ac magnetic susceptibility, as well as single-crystal neutron diffraction under various pressures up to 8 GPa and magnetic fields up to 8 T. Our results demonstrate that the ferromagnetic metallic ground state of n-type HgCr2Se4 is destabilized and gradually replaced by an antiferromagnetic, most likely a spiral magnetic, and insulating ground state upon the application of high pressure. On the other hand, the application of external magnetic fields can restore the ferromagnetic metallic state again at high pressures, resulting in a colossal magnetoresistance (CMR) as high as ∼3×1011% under 5 T and 2 K at 4 GPa. The present study demonstrates that n-type HgCr2Se4 is located at a peculiar critical point where the balance of competition between ferromagnetic and antiferromagnetic interactions can be easily tipped by external stimuli, providing a new platform for achieving CMR in a single-valent system.

Original languageEnglish
Article number047201
JournalPhysical Review Letters
Volume123
Issue number4
DOIs
StatePublished - Jul 22 2019

Funding

We thank Prof. Jianshi Zhou from University of Texas at Austin for the encouragement and the enlightening discussions. This work is supported by the National Key R&D Program of China (Grants No. 2018YFA0305700 and No. 2017YFA0302901), the National Natural Science Foundation of China (Grants No. 11888101, No. 11574377, No. 11834016, No. 11874400, No. 61425015, No. 11774399), the Strategic Priority Research Program and Key Research Program of Frontier Sciences of the Chinese Academy of Sciences (Grants No. XDB25000000, No. XDB07020100, and No. QYZDB-SSW-SLH013), and Beijing Natural Science Foundation (Z180008). A portion of this research used resources at the High Flux Isotope Reactor, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. Y. Y. J. and J. P. S. acknowledge support from the China Postdoctoral Science Foundation and the Postdoctoral Innovative Talent program.

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