Behavior of a cylindrical magnet

[overlook1977]

I noticed when I stick a cylindrical magnet on a smooth metal surface (longways) and roll the magnet along the surface, it does not roll smoothly. Instead, it seems to resist movment, then 'pop' forward into another position. It is almost as if the magnet has a preference on which side sticks to the surface. Anyone have any ideas about this?

 

[Astronuc]

The magnetic field or (orientation/distribution of domains in the cylindrical magnet) are not uniform, and therefore there is a preferred orientation, and that would interfere with the 'smooth' motion.