Non-magnetic impurities to induce magnetism in $\alpha$-PbO crystal structure

A new route to $d^0$ magnetism is established with help of the first principles methods. Non-magnetic interstitial impurities from group 14 in the periodic table are found to induce $p$-orbital magnetism in polycrystalline PbO-type structures. The half-filled $p$-orbitals occupied by two electrons is generated on the impurity site for which the ferromagnetic state of high stability is guaranteed by the first Hund's rule. Since the impurity is embedded between layers of the host, its atomic radius is a key to tune not only its solubility but also the magnetic behavior: the on-site stability of the spin polarized state grows with reduction of the atomic radius while losing in the long-rang order interactions. However, for impurities of smaller radius the weaker inter-site magnetic coupling can be compensated by their concentration as the impurity solubility limit is shifted to higher magnitudes.