- Ross H. Colman: Floating zone growth of low twinning stress magnetic shape memory crystals with low chemical segregation
- 20. 2. 2019, 14:10
- lecture room F2, first floor Ke Karlovu 5
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Abstract:
Magnetic shape memory alloys (MSMAs) have been considered for a range of technologically important applications such as actuating, sensing, pumping or energy harvesting. The majority of the proposed or realized applications require oriented single crystals and a range of single crystal growth techniques have been reported in the past, with directional solidification or Bridgman-Stockbarge being the most widely used. Due to the incongruently melting nature of Ni-Mn-Ga, the most widely studied MSMA, these techniques invariably lead to macroscopic chemical segregation along the crystal. Floating zone techniques can be used to grow crystals with sections of negligible macroscopic segregation, but additional complications with Ni-Mn-Ga growth make standard floating zone methods problematic. I will present our adaptations that have lead to the reproducible growth of single crystals with extremely low twinning stress. Also showing how the properties of our materials compare to industrially produced MSMAs.