But the hall effect is observed under conditions of low temperature and strong magnetic fields. I don't see that maintaining a low temperature should be difficult for a spaceprobe, which is isolated in a vacuum. Furthermore, there are newer materials like graphene, which has been found exhibit the Quantum Hall Effect at
room temperature!
http://www.cise.columbia.edu/nsec/research/nuggets.php?subsection=quantum
I'm wondering if the Quantum Hall Effect could perhaps be used in reverse, so that the flow of electrons would generate a strong magnetic field. That magnetic field could perhaps then be used to accelerate propellant mass.