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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 * 10^11 % 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 competion between ferromagnetic and antiferromagnetic interactions can be easily tipped by the external stimuli, providing a new platform for achieving CMR in a single-valent system.
We report on a positive colossal magnetoresistance (MR) induced by metallization of FeSb$_{2}$, a nearly magnetic or Kondo semiconductor with 3d ions. We discuss contribution of orbital MR and quantum interference to enhanced magnetic field response of electrical resistivity.
High quality HgCr$_2$Se$_4$ single crystals have been investigated by magnetization, electron transport and Andreev reflection spectroscopy. In the ferromagnetic ground state, the saturation magnetic moment of each unit cell corresponds to an integer
A field-induced crossover is observed in the resistivity and magnetization (M) of a La(0.7)Pb(0.3)MnO(3) single crystal. The field-dependence of the resistivity and M suggests that a small spin-canted species with mean-field-like interactions dominat
Quantum nematic phases are analogous to classical liquid crystals. Like liquid crystals, which break the rotational symmetries of space, their quantum analogues break the point-group symmetry of the crystal due to strong electron-electron interaction
Here we investigate antiferromagnetic Eu$_{5}$In$_{2}$Sb$_{6}$, a nonsymmorphic Zintl phase. Our electrical transport data show that Eu$_{5}$In$_{2}$Sb$_{6}$ is remarkably insulating and exhibits an exceptionally large negative magnetoresistance, whi