Mitigation of Vibrations during Ni-Mn-Ga Single Crystal Growth
Faculty Mentor Information
Paul Lindquist, Peter Mullner
Abstract
Ni-Mn-Ga exhibits a shape change in a variable magnetic field through the motion of twin boundaries. Defects such as grain boundaries increase the stress required to move twin boundaries and hamper the magnetic-field-induced shape change. Ni-Mn-Ga Single crystals are grown in-house using a modified Bridgman-Stockbarger technique. Occasionally, these single crystals contain small angle grain boundaries. This means that during the growth process small angle grain boundaries nucleate. We hypothesize that vibrations cause nucleation of these boundaries. To determine the source of vibrations, either internal from the growth apparatus, or external from the environment, we perform a systematic characterization of the vibrations on the growth apparatus. We plan on decoupling the growth chamber from the vibration sources with appropriate damping mats.
Mitigation of Vibrations during Ni-Mn-Ga Single Crystal Growth
Ni-Mn-Ga exhibits a shape change in a variable magnetic field through the motion of twin boundaries. Defects such as grain boundaries increase the stress required to move twin boundaries and hamper the magnetic-field-induced shape change. Ni-Mn-Ga Single crystals are grown in-house using a modified Bridgman-Stockbarger technique. Occasionally, these single crystals contain small angle grain boundaries. This means that during the growth process small angle grain boundaries nucleate. We hypothesize that vibrations cause nucleation of these boundaries. To determine the source of vibrations, either internal from the growth apparatus, or external from the environment, we perform a systematic characterization of the vibrations on the growth apparatus. We plan on decoupling the growth chamber from the vibration sources with appropriate damping mats.
Comments
Poster #W39