Development and Research of Crystals for Micro-Magneto-Mechanical Systems (DaRCoM³S)

The Heusler family of alloys represents a growing group of functionally important materials. The magnetic shape memory properties of Ni-Mn-Ga Heusler alloys are being investigated for a number of technological applications, but require high quality single crystal elements for many of the proposed functions. Ni-Mn-Ga alloys have a number of complex considerations that must be taken into account for crystal growth, and the first part of this project aims to mix a systematic experimental investigation, with computational modelling of the solidification process to understand the development of the ternary alloy microstructure under different conditions. The second part of this project links the observed microstructure to changes in magnetic shape memory properties, and specifically the properties of the alloys in top-down micro-fabricated devices, where microstructure of the parent crystal plays an enhanced role. The new understanding gained from studying Ni-Mn-Ga will then be applied to the growth and microfabrication of other technologically important Heusler alloys.