Thursday, March 22, 2012

More anomalous magnetoresistance

This is the latest in a series of posts cataloguing how there are wide range of strongly correlated metals which exhibit magnetoresistance which is qualitatively different from the semi-classical orbital magnetoresistance seen in most metals due to the Lorentz force. For the latter the magnetoresistance is maximal (zero) for the current and magnetic field perpendicular (parallel) to each other.

The data above is taken from a paper reporting measurements on the quasi-one-dimensional metal Li0.9Mo6O17, which also exhibits other non-Fermi liquid properties.
The graph shows the magnetic field dependence (in Teslan) of the relative change in the interlayer resistance with the field and current parallel to one another. The different curves correspond to different temperatures, increasing from 3 K to 50 K, from top to bottom.

1 comment:

  1. What are the ways to get positive MR with a parallel field? Here's what comes to my mind:

    1) Disruption of antilocalization
    2) Change in the density of states from band splitting
    3) Magnetic ordering
    4) In 2D systems, the magnetic confinement can reduce surface scattering
    5) By breaking a superconducting state
    6) ...

    What else?

    Are there common frameworks within which to think about the causes of positive magnetoresistance? Or do you just construct a list of effects, like I naively did?