Magnetotransport Properties of NiFe 1+x Mn 1-x Al Heusler Alloys

Heusler alloys have undergone extensive examination over the past two decades, both experimentally and theoretically, owing to their promising applications in the burgeoning field of spintronics. This presentation discloses the outcomes of a comprehensive investigation into the Heusler compound Nickel Iron Manganese Aluminum (NiFe 1+x Mn 1-x Al), which integrates theoretical analyses and calculations with experimental findings. This study compares the magnetic and electronic properties of NiFeMnAl for x = 0 and x = 0.25. In NiFeMnAl (x = 0), a dramatic increase in longitudinal resistance is observed at approximately 350 K, while for x = 0.25, this increase is absent. Additionally, the magnetoresistance is negative at lower temperatures for x = 0 but gradually becomes positive as the temperature approaches the upturn in resistance. In contrast, for x = 0.25, the magnetoresistance remains negative throughout the entire temperature range. It is likely that the change in the sign of magnetoresistance in the x = 0 sample is associated with the sharp upturn in longitudinal resistance. Furthermore, the sign of the current carriers also changes near the resistance upturn in the x = 0 sample. It is hypothesized that these changes in carrier sign and magnetoresistance are due to a significant shift in the distribution of current carriers of both signs, influenced by the band structure of the materials. Anticipated to be valuable for researchers actively involved in the practical implementation of spin-based electronics, this study contributes to the evolving understanding of Heusler alloys and underscores NiFe 1+x Mn 1-x Al's potential candidacy for advancements in spintronics, offering a promising avenue for future research and application development.