University of Minnesota
Aerospace Engineering and Mechanics
Spring 2003 Seminar Series



Growth and Characterization of Single Crystal Ferromagnetic Shape Memory Alloy Thin Films


Prof. Chris Palmstrom
Department of Chemical Engineering and Materials Science University of Minnesota


Abstract

Microactuators with large work output per cycle over long displacements are important for micro-electro-mechanical-systems (MEMS). The work output per unit volume of thin film shape memory alloy microactuators can exceed that of other microactuator mechanisms. The heat transfer rate during the heating and cooling associated with the martensitic transformation limits the actuator cycling frequency. The large magnetoelstic strain up to ~9.5% recently demonstrated in bulk single crystals of the ferromagnetic shape memory alloy Ni2MnGa makes it a promising candidate for a magnetic field driven actuator with the potential for a higher frequency of operation. The theoretical works of James, Luskin (UMN) and Bhattacharya (Caltech) suggest that single crystal thin film shape memory materials have distinct advantages over polycrystalline films for microactuator applications. This talk will emphasize the molecular beam epitaxial growth, characterization, processing and properties of single crystal ferromagnetic shape memory Ni2MnGa alloy films.

Friday, January 31, 2003
209 Akerman Hall
2:30-3:30 p.m.


Refreshments served after the seminar in 227 Akerman Hall.
Disability accomodations provided upon request.
Contact the AEM Office, 612-625-8000.