Phase Transformation Study of NiMn in NiFe/NiMn system

• Main Authors: Wei-Chih Lien, 連偉智
• Other Authors: Chih-Huang Lai
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/74813172238214835419

碩士 === 國立清華大學 === 材料科學工程學系 === 88 === NiMn has been shown to be a promising candidate as an AF material of spin valves. But as-deposited NiMn films are of fcc paramagnetic phase typically, post-annealing is required to attain fct antiferromagnetical phase. The previous research of NiMn mainly focus on parameters tunning to get high exchange field. The correlation of magnetic properties with phase transformation ratio of NiMn is seldom investigated. Now we study phase transformation of NiMn with TEM. From TEM diffraction pattern, we can distinguish the disordered fcc phase from ordered fct phase of NiMn. Dark field image contributed by (110) pattern only shown in order phase, can be used to calculate the order volume fraction of NiMn. We have applied DF TEM and accumulated sum to investigate ordering volume fraction and ordering parameter.