An investigation of structural and magnetotransport features of half-Heusler ScPtBi thin films

Abstract

Half-Heusler materials have grabbed enormous devotion from scientific community owing to their novel electrical, magnetic, and optical features. In this paper, we report on ScPtBi half-Heusler thin films grown at 200 and 300 °C on Ta/Si (100) substrates by magnetron co-sputtering. X-ray diffraction studies have proved a polycrystalline structure of the synthesized films. In addition, the film deposited at 300 °C has possessed a secondary PtBi phase. Cross-sectional microstructures and surface topographies of the films have been investigated via scanning transmission electron microscopy and scanning electron microscopy, respectively. The stoichiometric composition of the films has been investigated by X-ray photoelectron spectroscopy studies. Magnetotransport measurements, conducted by a conventional four-probe method in a temperature range of 5–300 K and at fields up to 9 T, have unveiled the existence of the weak antilocalization (WAL) effect in the examined samples. The phase coherence length, lφ, and the coefficient α have been extracted from the Hikami-Larkin-Nagaoka (HLN) relation. It has been shown that the extracted α values are between 800 and 1000, which highlights that the origin of the WAL effect results from the strong spin-orbit coupling (SOC) nature of the studied films rather than from topologically protected surface states. The Hall measurements performed at room temperature have shown that the major charge carriers are electrons and their mobility has been identified as 61 cm2.V−1.s−1 and 113 cm2.V−1.s−1 for the film deposited at 200 °C and 300 °C, respectively.