The Studies of Microstructure and Magnetic Properties of Mn-Bi Alloy Thin Films

• Main Authors: Cheng-Ying Wu, 吳振胤
• Other Authors: Ko-Wei Lin
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/aug4q8

碩士 === 國立中興大學 === 材料科學與工程學系所 === 106 === Rare-earth-free materials such as MnBi thin films have been intensively studied for their potential application in MEMS and hybrid electric vehicle motors, etc. In this study, the different magnetism of MnBi thin film structures via in-situ Ar ion-beam bombardment as well as with post deposition annealing processes was examined. The Ag(2nm)/MnBi(10、20nm) thin films were prepared on amorphous SiO2 substrates using a dual ion-beam sputtering dep-osition technique. Post deposition annealing was carried out at temperatures up to 550 ºC for 30 mins 、600 ºC for 30 mins 、700 ºC for 10 mins under vacuum. The structures of the MnBi thin films were characterized by XRD.The weak XRD reflection intensities are all of Ag; (111), (200), (220), and (311) and likely from the top thin Ag capping layer (2 nm); this implies that disordered MnBi phases are formed at this stage. The results are in agreement with those of TEM dark field images and the electron diffraction patterns. However, after the annealing processes LTP-MnBi films were obtained, as identified by XRD reflections at 2-thetha ~38º [(102)], ~42º [(110)], ~64º [(104)], and ~77º [(300)]. In addition, the annealed MnBi thin film exhibited better crystallinity with lattice constants a ~ 4.27 Å and c~ 6.15 Å, close to that of a bulk hcp MnBi. Similar XRD patterns were observed in the bombarded-MnBi and annealed [bombarded-MnBi], indicating that no textures changes were introduced by the in-situ Ar ion-beam bombardment during the MnBi growth.