Long-range ferromagnetic order in one-dimensional monatomic Co-chains

Abstract

Magnetism in low dimensions is a challenging problem for long time. As the dimensionality of the systems reduces, the fluctuations become more important and hence, the magnetic ordering tends to decrease. We find that one-dimensional monatomic chains of Co constructed on a Pt substrate exhibit long-range order below a threshold temperature in contrast to various theoretical results and expectations. The Co-chains have large localized orbital moment compared to that in the two-dimensional films and bulk Co. Therefore, the magnetic anisotropy energy is significantly large in this case. Thus, the observation of long-range ferromagnetic order in Co-chains may be attributed to the presence of anisotropy barriers due to the substrate.