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My research: properties of GaMnAs, a magnetic semiconductor

My research: properties of GaMnAs, a magnetic semiconductor. Elisa De Ranieri University of Cambridge. 2 nd VC, 07 Mar 2007. Semiconductors. Semiconductors conduct current only under certain conditions. Conduction can be related to the energy of the electrons in the system.

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My research: properties of GaMnAs, a magnetic semiconductor

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  1. My research: properties of GaMnAs, a magnetic semiconductor Elisa De Ranieri University of Cambridge 2nd VC, 07 Mar 2007

  2. Semiconductors Semiconductors conduct current only under certain conditions Conduction can be related to the energy of the electrons in the system Bands of E: conduction and valence band Conduction band  empty E Valence band  full

  3. Semiconductors E gap METALS INSULATORS SEMICONDUCTORS

  4. Ferromagnets Each atom behaves like a small magnet Vector represent the “magnetic moment” Moments couple and align in the same direction even with no applied field Domains are formed  energetic reason Moments align with the external magnetic field B

  5. I B V Magnetic semiconductors Semiconducting + magnetic properties density of charge carriers Resistance changes with the magnetic field orientation  anisotropic magneto resistance (AMR)

  6. Magnetic semiconductors Gold contacts Channel

  7. 50 m Devices… My device fabricated on a GaMnAs 1. Layout designed with AutoCAD 2. Fabrication metal evaporation, etching, electron beam lithography 3. Measurements

  8. Clean rooms

  9. Processes

  10. Measurements Cryostat  very low temperature Liquid helium inside

  11. Measurements Screen of the parameter analyser

  12. Measurements Data looks like this…

  13. Finally • Data needs to be interpreted in view of the theoretical knowledge of physics • useful discussion with experts in the field (supervisors, other academics) • publication of results on scientific journals

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