Experimental study of a new Heusler compound which contains molybdenum - Ti2MoAl

Abstract

Heusler alloys have been extensively studied, however, very little is known about such compounds which contain molybdenum at one of the Wyckoff sites, and not as a substituting or doping element. There is almost no experimental studies of such systems. We decided to study a Ti${}_2$${}_2$CrAl analogue, where Cr was substituted by its heavier cousin in the periodic table, Mo. We successfully synthesized the sample, and thoroughly investigated it with several experimental techniques. The magnetic susceptibility shows, that it is a paramagnetic metal, similar to Ti${}_2$${}_2$CrAl with a moderate thermopower of 15 $\mu$$\mu$V/K. Heat capacity does not show any anomaly. We also measured X-ray Photoelectron Spectroscopy (XPS) spectra and performed ab-initio Density Functional Theory (DFT) calculations. Heusler compound usually crystallizes in either simple or inverted structure - simple structure of Ti${}_2$${}_2$MoAl was confirmed by XRD (X-ray Diffraction) and DFT studies. On the surface, a minor contribution from inverted Heusler structure can be deduced from comparison of XPS with DFT calculations.