Damping of polycrystalline Ni-Mn-Ga, bulk, PLD, and sputtered thin film

Abstract

Polycrystalline Ni-Mn-Ga in bulk, pulsed laser deposition (PLD) thin film, and radio frequency (RF) sputtered thin film are studied. A thin film of direct current (DC) magnetron sputter deposited NiTi was also used in the study. A polycrystalline Ni-Mn-Ga bulk sample was measured to have a tan δ = 0.4925 and a maximum elastic modulus E = 7.3 GPa. Material characterization studies were performed on polycrystalline Ni-Mn-Ga thin films deposited by PLD onto single crystal (100) Si and (100) MgO substrates at substrate temperatures ranging from 550°C to 650°C. Damping measurements on RF sputter deposition of 1 μm Ni-Mn-Ga and 10 μm of NiTi both on copper substrates were performed in cantilever beam ring down tests. Results show 1 μm RF sputter deposited Ni-Mn-Ga thin film on a 54 μm copper substrate improves damping properties.