Honors Program Theses

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Honors Program Thesis (UNI Access Only)

First Advisor

Paul M. Shand

Abstract

Heusler alloys have been widely studied over the past two decades for their potential use in spintronics. This thesis project conducted a combined theoretical and experimental study of the Heusler compound Nickel Iron Manganese Aluminum (NiFe1+xMn1-xAl) with a focus on comparing the magnetic and electronic properties of the compound at two ratios of the Fe and Mn atoms for x = 0 and x = 0.25. With respect to the x = 0 sample, a sharp increase in longitudinal resistance at around 310 K was observed. In comparison to the x = 0.25 sample, however, this behavior is absent. It is further observed that the magnetoresistance is negative for x = 0 at lower temperatures, and gradually becomes positive as the temperature approaches the resistance upturn temperature of 310 K. In contrast, the x = 0.25 sample exhibited a negative magnetoresistance across the entire temperature range. The transition in the sign of magnetoresistance in the x = 0 sample, is fundamentally coupled with the sharp rise in longitudinal resistance. Furthermore, it was evident that the dominant charge carriers undergoes a sign change near this resistance upturn, hypothesized to be driven by a significant redistribution of current carriers which is likely influenced by the band structure of the material. Overall, this study helps clarify the transport behavior of NiFe1+xMn1-xAl and highlights its potential for future spintronics applications.

Year of Submission

2026

Department

Department of Physics

University Honors Designation

A thesis submitted in partial fulfillment of the requirements for the designation University Honors

Date Original

2026

Object Description

1 PDF file (14 pages)

Language

en

File Format

application/pdf

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