Soon-Gil Jung

Half-metallic magnetism, characterized by metallic behavior in one spin direction and semiconducting or insulating behavior in the opposite spin direction, is an intriguing and highly useful physical property for advanced spintronics because it allows for the complete realization of 100% spin-polarized current. Particularly, half-metallic antiferromagnetism is recognized as an excellent candidate for the development of highly efficient spintronic devices due to its zero net magnetic moment combined with 100% spin polarization, which results in lower energy losses and eliminates stray magnetic fields compared to half-metallic ferromagnets. However, the synthesis and characterization of half-metallic antiferromagnets have not been reported until now as the theoretically proposed materials require a delicate and challenging approach to fabricate such complex compounds. Here, we propose Cr₂Se₃ as the experimentally synthesizable half-metallic antiferromagnet. Our experimental and theoretical studies─including magnetic property measurements, spin-resolved density functional theory calculations, and tunneling magnetoresistance experiments─confirm its half-metallic antiferromagnetic behavior. We demonstrate that the 2D nonlayered Cr₂Se₃ synthesized via chemical vapor deposition offers an ideal platform for innovative spintronics applications and fundamental research into half-metallic antiferromagnets.

Emergent inhomogeneous electronic phases in metallic quantum systems are crucial for understanding high‐T_c superconductivity and other novel quantum states. In particular, spin droplets introduced by nonmagnetic dopants in quantum‐critical superconductors (QCSs) can lead to a novel magnetic state in superconducting phases. However, the role of disorders caused by nonmagnetic dopants in quantum‐critical regimes and their precise relation with superconductivity remain unclear. Here, the systematic evolution of a strong correlation between superconductive intertwined electronic phases and antiferromagnetism in Cd‐doped CeCoIn₅ is presented by measuring current–voltage characteristics under an external pressure. In the low‐pressure coexisting regime where antiferromagnetic (AFM) and superconducting (SC) orders coexist, the critical current (I_c) is gradually suppressed by the increasing magnetic field, as in conventional type‐II superconductors. At pressures higher than the critical pressure where the AFM order disappears, I_c remarkably shows a sudden spike near the irreversible magnetic field. In addition, at high pressures far from the critical pressure point, the peak effect is not suppressed, but remains robust over the whole superconducting region. These results indicate that magnetic islands are protected around dopant sites despite being suppressed by the increasingly correlated effects under pressure, providing a new perspective on the role of quenched disorders in QCSs.

When Ni is doped in Fe₃GaTe₂, the coercivity significantly increases even at room temperature, which is due to the domain pinning effect.