Abstract Scope |
Multifunctional Heusler-type magnetic shape memory alloys (SMAs) can be divided into two groups: ferromagnetic (FSMAs) and metamagnetic (MetaMSMAs). FSMAs are represented by NiMnGa. They exhibit giant magnetic field induced strain in martensitic phase due to mechanism of twin boundary motion. The MetaMSMAs, typically NiMnX (X=Sn, In,Sb), exhibit giant inverse magnetocaloric effect (MCE) in the temperature range of martensitic phase transformation (MT), contrary to NiMnGa alloys with merged MT and Curie temperature that show a giant conventional MCE. Three aspects from recent advances in aforementioned materials will be outlined.
1. Significant progress in the developments of high temperature FSMAs based on multicomponent NiMnGa(Co,Cu,Fe) alloys will be overviewed and discussed.
2. The mechanism of the large magnetostrain self-recovery in NiMnGa/silicone composites exhibiting magnetic field induced rubber-like effect will be disclosed.
3. It will be shown how to describe giant inverse MCE in MetaMSMAs and conventional MCE in FSMAs by Landau theory. |