2 research outputs found
[[alternative]]The observation of magneto-optic Kerr effect for Ni(100)
No full text[[abstract]]表面磁光柯爾效應(surface magneto-optic Kerr effect，SMOKE)是研究
磁性超薄膜表面磁性的新探測技術。本人將先行於空氣中自行設計、建造
SMOKE的實驗裝置，且先在空氣中測試Ni(100)晶片的柯爾效應，完成磁滯
曲線的測定，並找出影響柯爾訊號強弱的參數，確定出量測上的最佳參數
控制，以為超高真空環境下的SMOKE量測系統之準備。在我們的系統中，
檢偏器角度在0.3-0.7度時有最好的柯爾訊號與背景比例。量測縱向柯爾
訊號時，宜選擇較大的入射角，但有其上限，不能超過60度左右以上，反
之，量測法線方向柯爾訊號時，入射角的選擇則愈小愈好，愈能擁有較強
的柯爾訊號強度。所測得之Ni(100)晶片之磁滯曲線，表現出低殘磁、低
矯頑力、低磁滯能量損耗的特性，我們另以縱向柯爾效應 ,試圖找出
Ni(100)面上的結構對稱性，結果顯示柯爾效應亦能指出Ni(100)面為四對
稱的結構，且原子最接近的方向為Ni(100)面上之磁化易軸，即最高度對
稱的方向，而原子次接近的方向為Ni(100)面上第二易磁化的方向，原子
第三接近的方向則為 Ni(100)面上第三易磁化的方向。
The surface magneto-optic Kerr effect (SMOKE) is a new probe
for studying surface magnetism of ultrathin films. SMOKE is a
potent- ial technique, because SMOKE can measure hysteresis
curves of mo- nolayer-range magnetic films. Thus I established
a SMOKE measure- ment system in the air. I tested Kerr effect
of Ni(100) crystal and finished the measurement of hysteresis
curves. Determining the best parameter of the measurement was
also done. These provi- de for the preparation of SMOKE
measurement system in ultrahigh vacuum. For fitting the UHV
condition, the strength of the applied magne- tic field is
inverse proportional to the gap between the magnetic poles of
the electromagnet. Setting the analyzer angle to 0.3-0.7 degree
will give the best signal-to-background ratio in our system.
The longitudinal Kerr signal is more pronounced when the
incident angle is large, at least 55 degree. However, the polar
Kerr signal has opposite result. SMOKE hysteresis loops of
longitudinal Kerr effect and polar Kerr effect of Ni(100)
crystal are both very narrow. The behaviors of these hysteresis
curve show low remanence, low coercive force and low hysteresis
loss. For exploring the relationship between magnetization and
structures, we intend to find the symmetry of the Ni(100)
crystal by longitudinal Kerr effect. The result indicates that
Kerr effect can show fourfold rotation symmtery of the Ni(100)
crystal. And the easy axes of magnetization of the Ni(100)
plane is along the direction of the nearest-neighor atom. The
second easy axes of magnetization of the Ni(100) plane is along
the direction of the second neighbor atom. The third axes of
magnetization of the Ni(100) plane is along the direction of
the third neighbor atom.
The surface magneto-optic Kerr effect (SMOKE) is a new probe
Plan Showing the Condition of the Chippewa Cut Before and After the Late Improvements
No full textHistoric map showing the First and Second Welland Canal where the Welland River (Chippewa Creek) joins the Niagara River. The Chippewa cut is shown running adjacent to and Hog Island. A line of piles is marked in the Chippewa Cut. Also shown is a barracks. A notation at the top of Hog Island within the Welland River reads: “Proposed piers level with waters surface. Intended to diminish velocity of current through cut by reducing quantity of water discharged”.Text below the title reads: “The black lines showing the Condition of The Harbour in 1844 – The Blue representing the improvements Already effected (1845). The Red pointing out such as will still be necessary to render the harbor Easy of Access. The soundings marked in Red were taken under the direction of Capt. Boxer C.B. R.N 7th Sept. 1845.” Signed by author W. C. E. Holloway. Stamp on verso of Map Library's copy: "Map Division, Aug 26 1969, Public Archives of Canada." "H3/440-Chippewa-1846" written in pencil on verso."Authorship indicated: W. C. E. HollowayScale: [ca. 1:9,615]Digital reproduction: Library and Archives Canada, National Map Collection: NMC-3771. Original map size 43 x 53 cm. Black and white copy available in the Map, Data and GIS Library at Call Number: G 3462 W45 1845 H65.Georeferenced and modified by Map, Data and GIS Library, Brock University.Described in: Mapping Upper Canada, 1780-1867 / Joan Winearls. 1991. Reference no.: 149 (27
