Synthesis and characterization of half-Heusler ScPtBi films via three-source magnetron co-sputtering on Nb superconductor buffer layer

Abstract

The half-Heusler compounds exhibit simultaneous electrical, optical, and magnetic properties hence extensive research efforts have recently been dedicated to their development in diverse applications. Herein, we detail the fabrication and magnetic characterization of thin film ScPtBi was grown at 300 °C on Nb-buffered Si (100) single crystals (Nb/Si (100)) by using magnetron co-sputtering. X-ray diffraction examinations have unveiled the polycrystalline growth nature of the films. It is seen that the obtained ScPtBi thin film is strained by 1.4% compared to the single crystal of ScPtBi. The morphological observations, conducted by scanning electron microscopy (SEM), revealed that the Nb buffer layer has a smooth and crack-free surface. Moreover, it has been observed that the Bi islands are formed on the surface of ScPtBi film, which is confirmed by the high-resolution scanning transmission electron microscopy (HR-STEM) analyses. The presence of the weak antilocalization (WAL) effect has been observed in the samples. The Hikami-Larkin-Nagaoka (HLN) equation was used to analyze experimental data, aiming to calculate the phase coherence length (lφ) and the coefficient α. As the temperature increased, the phase coherence length decreased from 39 nm to 24 nm. The coefficient α was determined to be in the range of 500 to 1100. As a result, it has been concluded that the presence of the WAL effect might be connected to the strong spin-orbit coupling (SOC) nature of the films instead of from topologically protected surface states.