Fe atoms were steamed on Si(111)-7×7 surface, which had been saturated by CH3OH. Aim to greatly enhance the magnetic performance, nitriding experiments were implemented and adjusted on the existing linear Fe clusters. First of all, the dissociation of CH3OH adsorption process was deducted in detail, which laid a good foundation for the better use of surface quasi-potential. Further to solve the coming problems like weak linearity and low nitriding effect, the formation mechanism of iron-nitride

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... was explored. Atomic layers of Fe deposition are confirmed as the key to NH3 dissociation process (at room temperature). Specifically, the higher Fe atomic layer contacted by NH3, the weaker influence of surface quasi-potential. With the introduction of Ar, Fe deposition could be controlled at 1-2 atomic layers, result in good NH3 dissociation and nitriding efficiency. Combing with magnetic performance result, the density of residual magnetization is improved from 1.5E-0.5 emu to 7.0E-0.5 emu, forming an obvious linear structure. It is also proved that our new linear iron-nitride clusters will maintain good stability with the improvement of nitriding efficiency.PACS: 07.79.Cz; 81.15.-z; 75.75.Fk