Structure and magnetization of MnSb thin films deposited at different substrate temperatures

Abstract

The influence of substrate temperatures on the structure, morphology, magnetic properties, and surface composition of MnSb films prepared by hot-wall epitaxy are analyzed. All the films are found to be single phase with nickel arsenide (NiAs) crystal structure. X-ray photoelectron spectroscopy study on the core levels reveals that the surface oxidation of the films is not very much enhanced with increasing substrate temperature except for a variation in the concentration of Sb2O3 and MnO2 near the surface-air interface. The decrease in saturation magnetization for the films is attributed to an increase in the manganese oxide content as substrate temperature increases. It is also observed that preferential Mn segregation from the grains to the grain boundaries will reduce the magnetic coupling between grains and thus increase coercivity and decrease coercivity squareness.

Stoichiometry, contamination and microstructure of MnSb(0001) surfaces

“…They interpreted TOA-dependent XPS measurements of the surface oxides of these island arrays as predominantly a combination of MnO 2 and Sb 2 O 3 , with the latter increasing in concentration nearer the surface, and no metallic Sb [29]. The near-surface structure of our air-stored MBE-grown films MnSb(0 0 0 1) is also significantly chemically stratified.…”

“…The approximate stratification of the contamination layer is therefore: MnSb (bulk)-metallic Sb-Sb oxides-Mn oxides (surface). It is not surprising that the ambient, room temperature contamination layers develop very differently to those occurring at high temperature in HWE: in the latter case metallic Sb is rapidly desorbed or oxidized and the high Sb overpressure allows an Sbrich surface oxide layer to remain [29].…”

“…Low et al grew MnSb by hot-wall epitaxy (HWE) on GaAs(0 0 1) and obtained micron-sized epitaxial islands [29]. They interpreted TOA-dependent XPS measurements of the surface oxides of these island arrays as predominantly a combination of MnO 2 and Sb 2 O 3 , with the latter increasing in concentration nearer the surface, and no metallic Sb [29].…”

Magnetism and Mn Clustering in (In,Mn)Sb Magnetic Semiconductors

“…The values of ∆ so for atomic manganese, metallic phase Mn and compound MnSb are 10.6, 11.25, and 11.6eV, respectively. [39][40][41] Figure 3 shows the Mn 2p corelevel XPS spectra of the samples grown on InSb at 420°C. All the spectra shown are measured at the depth where there is a maximum Mn concentration in the films.…”

MnSb inclusions in the GaSb matrix studied by X-ray absorption spectroscopy

“…In contrast to MnAs, forming the MnSb inclusions by an implantation process encounters many difficulties (Wolska et al, 2010). On the other hand, studies on the MBE grown thin layers showed that already in pure material, MnSb does not form smooth surface but tends to form big islands or columns (Low et al, 1999;Lawniczak-Jablonska et al, 2009). This leads to the other advantage which is possibility to form the hexagonal MnSb precipitates directly during the MBE process without subsequent annealing.…”