  We introduce new type of ferromagnets, CaN and SrN, which were designed using
first-principles calculations. These are half-metallic ferromagnets and they
have magnetic moments of 1 $\mu_{\rm B}$ per chemical formula unit. Out of the
typical structures of binary compounds, the rock-salt structure is the most
stable form for both CaN and SrN. The majority of the magnetic moment of these
compound originates from the N sites since the $p$ states of N are
spin-polarized. Their formation energies were calculated and the results show
that it should be feasible to synthesize these materials. The structural
stability of CaN was confirmed by performing first-principles molecular
dynamics simulations. We propose a synthesis process for CaN basd on the
first-principles.
