Morphology, surface structures, and magnetic properties of MnSb thin films and nanocrystallites grown on graphite

Abstract

MnSb nanocrystallites and thin films have been grown on highly oriented pyrolytic graphite (HOPG) by codeposition of Mn and Sb in ultrahigh vacuum. The surface morphologies of these MnSb structures were investigated using in situ scanning tunneling microscopy (STM). With 5nm nominal deposition, MnSb nanocrystallite chains with a typical width of 50nm are formed along the HOPG step edges. A continuous MnSb film is formed after Mn and Sb codeposition on a HOPG precovered with an Sb wetting layer. The MnSb thin film surface exhibits mostly hexagonal-shaped MnSb(0001) plateaus of a few atomic layers in height. Atomic-resolution STM images revealed 2×2 and (23×23)R30° reconstructions on the MnSb(0001) surface and a 2×1 superstructure on MnSb(101¯1). X-ray photoelectron spectroscopy study showed that the Mn 2p peaks shift 2.5eV with respect to that of elemental Mn, indicating the formation of MnSb compound. Vibrating sample magnetometry measurement showed that the MnSb film is ferromagnetic at room temperature, and is composed of mostly (0001)-oriented grains as well as some with other orientations.

Depth-dependent magnetism in epitaxial MnSb thin films: effects of surface passivation and cleaning

“…High quality epilayers more than ≈50 nm thick typically show in-plane coercivities below 20 Oe but we observe no correlation between film thickness and coercivity. Probably due to the high quality and uniformity of our films, these values of coercivity are significantly lower than those found by other groups for MnSb films grown on other substrates [26][27][28]. For example, Low et al [27] measured coercivities between 257 and 571 Oe for granular MnSb films grown by hot wall epitaxy on GaAs(001), which showed no out-of-plane hysteresis.…”

Stoichiometry, contamination and microstructure of MnSb(0001) surfaces

“…MnAs [20,21] and MnSb [22,23] surfaces have been investigated by several groups, but quantitative structural information is very limited [21]. The surface electronic structure of MnSb was investigated using electron spectroscopy, but the observed surface states did not correlate with the reconstruction and theoretical predictions [24].…”