Carpenter, D.; Chmielus, M.; Rothenbühler, A.; Schneider, R.; Müllner, P.: Application of Ferromagnetic Shape Memory Alloys in Power Generation Devices. In: G. B. Olson ... [Ed.] : Proceedings of the International Conference on Martensitic Transformations : June 29 - July 05, 2008, Icomat, Santa Fe, New Mexico, USA Warrendale, Pa.: TMS , 2009. - ISBN 978-0-87339-745-2, p. 365-369
http://www.gbv.de/dms/tib-ub-hannover/634468944.pdf
10.1002/9781118803592.ch53
Abstract:
By the inverse magnetoplastic (IMP) effect, twin boundaries in magnetic shape memory alloys (MSMA) can be reoriented by applying a mechanical stress. The result of this applied stress is a plastic deformation, as well as a change of magnetization. Used in conjunction with a coil, this changing magnetic field was harnessed in a power generation device to produce an electrical signal. With the application of a static bias magnetic field, as well as the removal of the applied stress, the twin boundaries reoriented themselves and restored the transducer’s initial geometry. This process was repeated via a periodic force applied with a variable speed motor, and was performed at room temperature and with compact permanent magnets. A Ni-Mn-Ga MSMA single crystal with approximate dimensions 5.4 x 3.9 x 3.1 mm³ served as magnetomechanical transducer. Actuation frequencies up to 2.25 Hz were applied resulting in an output voltage of up to 3.8 mV and a power output of up to 80 nW.