Vanadium sacrificial layers as a novel approach for the fabrication of freestanding Heusler Shape Memory Alloys

TL;DR

This paper introduces a new method for creating freestanding Heusler shape memory alloy films using vanadium sacrificial layers, enabling detailed study of substrate effects on phase transitions.

Contribution

It presents a novel fabrication technique employing vanadium sacrificial layers for freestanding Heusler alloy films, facilitating analysis of substrate constraint effects.

Findings

Successful fabrication of freestanding Heusler films via vanadium sacrificial layers

Crystallization and epitaxial growth conditions identified

Substrate constraints significantly influence Martensitic transition behavior

Abstract

In this study we report a method for the preparation of freestanding magnetocaloric thin films. Non-stoichiometric Heusler alloys Ni-Mn-Sn, Ni-Co-Mn-Sn and Ni-Co-Mn-Al are prepared via sputter deposition. A sacrificial vanadium layer is added between the substrate and the Heusler film. By means of selective wet-chemical etching the vanadium layer can be removed. Conditions for the crystallization of Vanadium layers and epitaxial growth of the Heusler films are indicated. Magnetic and structural properties of freestanding and as-prepared films are compared in detail. The main focus of this study is on the influence of substrate constraints on the Martensitic transistion.