is Íslenska en English

Lokaverkefni (Meistara)

Háskóli Íslands > Verkfræði- og náttúruvísindasvið > Meistaraprófsritgerðir - Verkfræði- og náttúruvísindasvið >

Vinsamlegast notið þetta auðkenni þegar þið vitnið til verksins eða tengið í það: http://hdl.handle.net/1946/24952

Titill: 
  • Titill er á ensku High frequency magnetic field sensors
Námsstig: 
  • Meistara
Útdráttur: 
  • Útdráttur er á ensku

    This thesis presents the results of two independent studies. The first study is focused around the anomalous Hall effect in FexPt1-x thin films. The anomalous Hall voltageis measured while the sample passes an alternating current through it. This is done at a few different frequencies. It turns out that the anomalous Hall voltage oscillates,
    in each measurement, with the same frequency as the current. The power of those frequencies remains constant for frequencies below 123.7 kHz, but above that the power starts to drop dramatically. This is believed to be caused by limitations in the FePt samples, rather than limiting factors of the anomalous Hall effect. The second study is focused around the magnetic anisotropy of Ni81Fe19. The anisotropy is measured in films of different thicknesses. From that data the surface anisotropy constant in the films is evaluated as Ks = (8±2)×〖10〗^4 erg/cm^2. It is also concluded that for thicknesses above 100 nm the films are considered bulk with an anisotropy constant of Ku = 1440±120 erg/cm^3. The anisotropy constant of NiFe films was also measured in samples grown with different deposition conditions. The results show that the anisotropy is minimized if the deposition pressure is low, the substrate temperature during growth is higher rather than lower, and the substrate in rotated at higher speed, rather than lower, during growth. The quality of the hysteresis in the samples is maximized if they are deposited in an in situ magnetic field that reinforces the natural easy axis of the deposition.

Styrktaraðili: 
  • Asaf Grosz of Ben-Gurion University of the Negev in Irael.
    Micro magnetics Inc.
    Gang Xiao of Brown University.
Samþykkt: 
  • 6.6.2016
URI: 
  • http://hdl.handle.net/1946/24952


Skrár
Skráarnafn Stærð AðgangurLýsingSkráartegund 
Egill Ingi Jacobsen - MS thesis.pdf1.58 MBOpinnHeildartextiPDFSkoða/Opna