Helical spin structure of 1D chains with hybridized boundaries*

We have synthesized and studied quantitatively the structure and magnetic properties of ultra-short 1D Fe chains subject to various boundary conditions. The length of Fe chains are controlled by using iron phthalocyanine(FePc) thin films and FePc/ metal-free phthalocyanine(H₂Pc) superlattices(SLs). Their boundary conditions are controlled by electronic hybridization at the end of the chains. The local bonding environment was determined from element selective XAS, and the angular dependence of Spin and orbital moment was resolved by XMCD. DFT calculations provided a fundamental understanding of the structural and electronic properties of 1D Fe chains subject to different electronic environments. The coercive field increases with the iron chain length with hybridized boundaries, whereas in chains not subject to hybridization the coercive field remains constant. The slow magnetic relaxation of 1D Fe chains at different freezing temperatures was extracted from the magnetic remanence evolution with time. A quantitative, semi-classical model based on the DMI, implies the presence of an unusual Helical spin structure which arises from hybridized boundaries