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

Abstract

In this study we report a method for the preparation of freestanding magnetocaloric thin films. Nonstoichiometric Heusler alloys Ni-Mn-Sn, Ni-Co-Mn-Sn and Ni-Co-Mn-Al are prepared via sputter deposition. A sacrifial vanadium layer is added between the substrate and the Heusler film. By means of selective wetchemicals 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.