First-principles method has been applied to calculate the structural, electronic and magnetic properties of the Al_1-xMn_xN alloys (with x = 0.0, 0.125, 0.25, 0.375, 0.50, 0.625, 0.75, 0.875 and 1.00) in the zinc blende structure (ZB), using FP-LAPW method within the spin-polarized density functional theory. We have studied the band structure and magnetic moment as a function of the lattice parameter of the MnN compound and the ternary alloys Al_1-xMn_xN. The magnetization increases as the lattice parameter increases and tends to saturate at the value 4μ_B for MnN and 8 μ_B for the ternary alloys. We also found that the ternary alloys with x = 0.125 and 0.25 are ferromagnetic in nature and candidate to be half-metallic material; the majority spin states show metallic behavior and the minority spin states show semiconducting behavior. The three concentrations x = 0.375, 0.5 and 0.625 are founded to be semi-metals within the PBE-GGA approach, while they are half metals within the modified Becke-Johnson (mBJ-GGA) approach.

The remaining concentrations are found to be semi-metals. It was found that the lattice parameter and the total magnetic moment strongly depend on the Manganese (Mn) concentration.