Magnetostriction of the antiferromagnetic Ir20Mn80 thin films

• Main Authors: Huang-Sheng Liu, 劉皇昇
• Other Authors: Wei-Chun Cheng
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/66694646171143511398

碩士 === 國立臺灣科技大學 === 機械工程系 === 96 === In this study, we have made Ir20Mn80 antiferromagnetic thin films on a Corning 0211 glass substrate, respectively, by sputtering method. Sample configuration is glass (110 �慆)/Ir20Mn80 (X Å)/Ta (100 Å), When X=1500 Å, 1000 Å, 500 Å, 300 Å and 100 Å. To anneal the sample, we had the annealing temperature 250 ℃, annealing time 1 hour. There were two sets of samples: one is annealing, the other is without. We analyzed the magnetic property by vibrating sample magnetometer (VSM). The crystalline structure and the phase were analyzed by XRD. Young’s modulus of thin film (Ef) was measured by the nano-indentation techniqe. Magnetostriction (��) of different thickness (X) were measured the change of electric capacitance, when the field (H) was varied. We used the transmission electron microscope (TEM) to observe one the change of grain size (D) before and after annealing. After analysing via the above-listed instrument, we know that the Ir20Mn80 thin film grow with the <200> texture, Ef=180 GPa before annealing, Ef=170 GPa after annealing. As to the magnetostrictive part, the ���nvalue has been decrease when the thickness decreases, i.e. from -30 ppm to -390 ppm. After annealing, the the ���nvalue has been reduced again. Form TEM observation, for the X=1500 Å of Ir20Mn80 thin film, before annealing D=17 nm, and after annealing D has been grown to 22 nm. So, after annealing, the magnetostriction of Ir20Mn80 thin film will be better than before annealing. Because after annealing, it had enough time and driving force to precede the three steps of annealing. That will also make the Young’s modulus drop, the grain size increase, and get better magnetostriction.