Magnetic-Competition-Induced Colossal Magnetoresistance in $$n$$-Type $$\mathrm{HgCr_2Se_4}$$ Under High Pressure

Journal Article · 22 July 2019 · Physical Review Letters

DOI: https://doi.org/10.1103/PhysRevLett.123.047201 · OSTI ID:1550746

Sun, J. P.  ^[1]; Jiao, Y. Y. ^[2]; Yi, C. J. ^[1]; Dissanayake, S. E. ^[3]; Matsuda, M. ^[4]; Uwatoko, Y. ^[5]; Shi, Y. G. ^[6]; Li, Y. Q. ^[6]; Fang, Z. ^[6]; Cheng, J. -G. ^[6]

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1. Chinese Academy of Sciences, Beijing (China). Beijing National Lab. for Condensed Matter Physics and Inst. of Physics; Univ. of Chinese Academy of Sciences, Beijing (China). School of Physical Sciences
2. Chinese Academy of Sciences, Beijing (China). Beijing National Lab. for Condensed Matter Physics and Inst. of Physics; Wuhan Univ. of Science and Technology, Wuhan, Hubei (China). Faculty of Science
3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Neutron Scattering Division; Duke Univ., Durham, NC (United States). Dept. of Physics
4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Neutron Scattering Division
5. Univ. of Tokyo, Kashiwa, Chiba (Japan). Inst. for Solid State Physics
6. Chinese Academy of Sciences, Beijing (China). Beijing National Lab. for Condensed Matter Physics and Inst. of Physics; Univ. of Chinese Academy of Sciences, Beijing (China). School of Physical Sciences; Songshan Lake Materials Lab., Dongguan, Guangdong (China)

The $$n$$-type HgCr₂$$\mathrm{Se_4}$$ exhibits a sharp semiconductor-to-metal transition (SMT) in resistivity accompanying the ferromagnetic order at $${T_C}$$ = 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 HgCr₂$$\mathrm{Se_4}$$ 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 $$\mathrm{~ 3 × 10^{11}}$$% under 5 T and 2 K at 4 GPa. The present study demonstrates that $$n$$-type HgCr₂$$\mathrm{Se_4}$$ 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.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1550746
• Journal Information: Physical Review Letters, Vol. 123, Issue 4; ISSN 0031-9007
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English