Effect of alloying of magnetic and non-magnetic low reactivity atoms into atomic chain

Abstract

We have theoretically studied the possible formation of evenly mixed Pt–X, Au–X, Pd–X bimetallic atomic chains (ACs) with X = Co, Fe, and Ni. The results show that Pt–Fe ACs are the most energetically favorable. First principles calculations revealed that the energy of alloy formation is dependent on the d-band filling of the magnetic component (Fe, Co, and Ni). Thus, we found that formation of stable evenly mixed ACs with Ni atoms as the magnetic component is not possible. Moreover, we found that the alloying energy is dependent on the geometry of the AC. We found that the energy of alloy formation remains unchanged in linear ACs and drastically decreases by ∼1 eV under chain contraction, accompanied by a transition of the AC from a linear to a zigzag configuration. Our electronic structure calculations revealed the emergence of a ferromagnetic transition under stretching of the AC in all the bimetallic chains with Fe atoms as the magnetic component (Pt–Fe, Pd–Fe, and Au–Fe) from the ferromagnetic to the antiferromagnetic state.