RESUMEN
The influence of the W-doping on the martensitic transformation, magnetic properties and exchange bias (EB) effect in the Ni47Mn40Sn13-xWx(x= 0, 0.5, 1, 1.25 at.%) magnetic shape memory alloys has been investigated. It is found that the W-doping causes a simultaneous reduction of both the ferromagnetic (FM) exchange coupling and enhancement of the magnetic anisotropy, leading to a decrease of the magnetic moment of the low-temperature phase and to a higher attainable EB. The magnetic memory measurements reveal the presence of a glassy magnetic ground state, which can significantly impact the reduction of magnetization and enhancement of EB in the studied bulk alloys. It is argued that the glassy magnetic ground state originates from the partial magnetic disorder resulting from the correlation between the antiferromagnetic and FM states. The results demonstrate that the doping by W instead of Sn is an efficient tool to tailor the EB effect in the Ni-Mn-Sn-based Heusler alloys, whereby they are promising for spintronic applications.
RESUMEN
Motivated by the recent experimental discovery of C6N7monolayer (Zhaoet al2021Science Bulletin66, 1764), we show that C6N7monolayer co-doped with C atom is a Dirac half-metal by employing first-principle density functional theory calculations. The structural, mechanical, electronic and magnetic properties of the co-doped C6N7are investigated by both the PBE and HSE06 functionals. Pristine C6N7monolayer is a semiconductor with almost isotropic electronic dispersion around the Γ point. As the doping of the C6N7takes place, the substitution of an N atom with a C atom transforms the monolayer into a dilute magnetic semiconductor, with the spin-up channel showing a band gap of 2.3 eV, while the spin-down channel exhibits a semimetallic phase with multiple Dirac points. The thermodynamic stability of the system is also checked out via AIMD simulations, showing the monolayer to be free of distortion at 500 K. The emergence of Dirac half-metal in carbon nitride monolayer via atomic doping reveals an exciting material platform for designing novel nanoelectronics and spintronics devices.