Titanium Nitride as a Seed Layer for Heusler Compounds

TL;DR

This study demonstrates that titanium nitride (TiN) can serve as an effective seed layer for growing high-quality Heusler compound thin films, improving their magnetic properties for potential spintronic applications.

Contribution

It provides a comprehensive analysis of TiN as a seed layer, including its crystallographic, electrical, and magnetic effects on Heusler thin films, which was not previously detailed.

Findings

TiN exhibits low resistivity and high thermal stability as a seed layer.

TiN buffer enhances coercivity and squareness ratio in Mn2.45Ga films.

Co2FeAl films show good crystallinity when grown on TiN at room temperature.

Abstract

Titanium nitride (TiN) shows low resistivity at room temperature, high thermal stability and thus has the potential to serve as seed layer in magnetic tunnel junctions. High quality TiN thin films with regard to the crystallographic and electrical properties were grown and characterized by X-ray diffraction and 4-terminal transport measurements. Element specific X-ray absorption spectroscopy revealed pure TiN in the bulk. To investigate the influence of a TiN seed layer on a ferro(i)magnetic bottom electrode, an out-of-plane magnetized Mn2.45Ga as well as in- and out-of-plane magnetized Co2FeAl thin films were deposited on a TiN buffer, respectively. The magnetic properties were investigated using a superconducting quantum interference device (SQUID) and anomalous Hall effect (AHE) for Mn2.45Ga. Magneto optical Kerr effect (MOKE) measurements were carried out to investigate the magnetic properties of Co2FeAl. TiN buffered Mn2.45Ga thin films showed higher coercivity and squareness ratio compared to unbuffered samples. The Heusler compound Co2FeAl showed already good crystallinity when grown at room temperature.