Interfacial charge transfer induced antiferromagnetic metals and magnetic phase transition in (CrO2) m /(TaO2) n superlattices

As a class of remarkable spintronic materials, intrinsic antiferromagnetic (AFM) metals are rare. The exploration and investigation of AFM metals are still in its infancy. Based on first-principles calculations, the interface-induced magnetic phenomena in the (CrO2)( m )/(TaO2)( n ) superlattices are investigated, and a new series of AFM metals is predicted. Under different ratios of m:n 2)( m )/(TaO2)( n ) superlattices exhibit three different phases, including the AFM metal, the AFM semiconductor, and the ferromagnetic (FM) metal. In the AFM semiconducting phases, the intra-CrO2-monolayer magnetic exchange interaction is systematically discussed, corresponding to m = 1 or m = 2. Both the localization of the Cr 3 d orbitals and the crystal-field splitting are crucial for magnetic ordering in super-exchange interactions. Based on the analyses of the AFM semiconducting phases with m = 1 and m = 2, the mechanisms of AFM metallic phases with radios of m:n < 1/2 1/22)(1)/(TaO2)(3) superlattice, and a tensile strain of 7% in the (CrO2)(2)/(TaO2)(3) superlattice. The phase diagram of the (CrO2)( m )/(TaO2)( n ) superlattices is obtained as a function of the layer thickness. This work provides new insights about realizing and manipulating AFM metals in artificial superlattices or heterostructures in experiments.

Automated summary

In this study, a new series of AFM metals is predicted in (CrO2)(m)/(TaO2)(n) superlattices, and the interface-induced magnetic phenomena are investigated. The magnetic exchange interaction in the AFM semiconducting phases is systematically discussed, and the mechanisms of AFM metallic phases are revealed. This work provides new insights about realizing and manipulating AFM metals in artificial superlattices or heterostructures.