  Antiferromagnetic materials have a vanishingly small net magnetization, which
generates weak dipolar fields and makes them robust against external magnetic
perturbation and rapid magnetization dynamics, as dictated by the geometric
mean of their exchange and anisotropy energies. However, experimental and
theoretical techniques to detect and manipulate the antiferromagnetic order in
a fully electrical manner must be developed to enable advanced spintronic
devices with antiferromagnets (AFMs) as their active spin-dependent elements.
Among the various AFMs, conducting AFMs offer high electrical and thermal
conductivities and strong electron-spin-phonon interactions. Noncollinear
metallic AFMs with negative chirality, including Mn3Sn, Mn3Ge, and Mn3GaN,
offer rich physics that arises from their topology. In this review article, we
introduce the crystal structure and the physical phenomena observed in negative
chirality AFMs. Experimental and theoretical advances related to
current-induced dynamics on the spin structure of Mn3Sn are discussed. We then
present a potential AFM spintronic device that can serve as a non-volatile
memory, high-frequency signal generator, neuron emulator, and even a
probabilistic bit, depending on the design parameters and the input stimuli,
i.e., amplitude and pulse width of the injected spin current and the external
magnetic field. In this device, spin-orbit torques can be used to manipulate
the order parameter, while the device state can be read via tunneling
magnetoresistance. We also present analytic models that relate the performance
characteristics of the device with its design parameters, thus enabling a rapid
technology-device assessment. Effects of Joule heating and thermal noise on the
device characteristics are briefly discussed. We close the paper by summarizing
the status of research and present our outlook in this rapidly evolving
research field.
