Unveiling the Antiferromagnetic Properties of Cr2Pbn (n = 3-20) Clusters

Abstract

Assembling antiferromagnetic (AFM) clusters is perhaps an effective way to construct AFM materials to meet the increasing demand for micro/nano spintronic devices, which promotes the exploration of AFM clusters. Herein, we unveil the structural evolution, electronic, and AFM properties of Cr₂Pb_n (n = 3-20) clusters based on density functional theory (DFT) calculations. It is found that the Cr impurities prefer the central axis positions of the skeleton in these Cr₂Pb_n (n = 3-20) clusters. For sizes n ≤ 6, their structures are exohedral structures with the two Cr atoms exposed outside, endohedral Cr@Pb_n configuration with one Cr atom interior appears at size 7, and the resulting endohedral structure is then gradually covered by the additional Pb atoms to form endohedral Cr₂@Pb_n structures for n = 15-20. All Cr₂Pb_n clusters are antiferromagnets, except for the ferrimagnetic Cr₂Pb₁₁ with a net magnetic moment of 2 μ_B. The discovered stable Cr₂Pb₁₇ cluster can assemble into dimers and trimers while maintaining its geometric structure and AFM properties, indicating the potential of becoming structural units for cluster-assembled AFM materials.

Keywords: antiferromagnetic coupling; doubly chromium doped lead clusters; magnetic properties; structural evolution.