Tailoring the Thermal Stability of Microstructure and Magnetic Properties of Galfenol Film on Single-Crystal Diamond Through Various Interlayers

Abstract

The coupling of a magneto-strictive galfenol (FeGa) film with single-crystal diamond (SCD) offers a promising configuration for high-temperature magnetic sensing application. However, the large lattice mismatch between FeGa and diamond hinders the development of high-performance FeGa film on SCD. In this work, various interlayers of Ti, WC, and WC/Ti films are investigated to reduce the lattice mismatch and improve the interface adhesion between FeGa film and SCD, as well as tailor the magnetic properties of FeGa film. The FeGa films grown on the SCD and Ti/SCD substrates exhibit (220)-oriented body-centered cubic (BCC) phases, while those on the WC/SCD and WC/Ti/SCD substrates show (200)-oriented BCC phases. The thermal stability of the microstructures, phase structures, and magnetic properties of the FeGa films are greatly enhanced by the addition of interlayers. The FeGa films with the FeGa/SCD, FeGa/Ti/SCD, FeGa/WC/SCD, and FeGa/Ti/WC/SCD structures show high thermal-stability of surface morphologies, roughness, phase structures, and magnetic properties under annealing temperatures up to 573 K, 773 K, 573 K, and 673 K, respectively. The present work provides a guidance for the development of high thermal-reliability and high-performance of FeGa/SCD-based devices in magnetic sensing under extreme conditions.

Keywords: Galfenol film, Single-crystal diamond, Interlayers, Thermal stability, Microstructure, Magnetic properties