Resistivity & Hall Effect

Experiment Guide
1.  Pre-Lab
2.  Part 1
3.  Part 2
Related Material
1.  Melissinos (2003)
63 - 71
2.  HP 3478A Multimeter Manual
Useful Links
1.  Wikipedia Article
2.  Quantum Hall Effect
3.  Spin Hall Effect
4.  Fractional Quantum Hall Effect
5.  Nobel Prize I
6.  Nobel Prize II










Electrical resistivity is a basic measure of how well a material conducts electrical current. When a magnetic field is applied non-collinearly to the current direction, the Lorentz force bends the trajectory of charge carriers and leads to a potential difference. This is known as the Hall effect, named after Edwin Hall who discovered it in 1879. A figure of merit is the Hall coefficient, which is characteristic of charge carriers present in the material. There are a few variations of this effect (Nobel Prizes in 1985, 1998), see discussions at the Useful Links. Additionally, when certain magnetic heterostructures are placed inside a magnetic field, the spin-dependent scattering process can lead to a large change in their electrical resistance, or a giant magnetoresistance effect (GMR, Nobel Prize in 2007). In this experiment you will first explore electrical resistivity and the GMR effect in a metallic Co/Cu multilayer thin film; you will then measure the temperature dependent resistivity and Hall coefficient of a semiconductor germanium crystal.