▎ 摘　　要

Exploring half-metallic nanostructures with a high Curie temperature and a wide half-metallic gap is a crucial solution for developing high-performance spintronic devices. Using the first-principles method, we design a new magnetic structure based on edge modification of armchair-edged graphene nanoribbons by Mn and F atoms (AGNR-Mn-F2). It is found that such a structure is an excellent half-metal with a wide bandgap (similar to 1.2 eV) and a stable magnetic ordering by a very high Curie temperature (T-c > 700 K) as well as being predicted to stably exist in a very large chemical potential range in experiment by the Gibbs free energy. And it is also shown that it possesses an outstanding magnetic device nature, such as a spin polarization of 100% in a very large bias region, a dual spin diode-like rectification ratio up to 105, and a spin-valve feature with a giant magnetoresistance approaching 108%, indicating a promising application for developing spintronic devices.