Fig. 1.

Schematics showing how the Hall resistance can be more sensitive to domain switching than the longitudinal resistance, for geometric reasons. (A) A narrow strip containing two types of domains that differ significantly in carrier mobility and density—e.g., domains A (dark blue) are more metallic than domains B (pink). When domain A is between the contacts C1 and C2, the Hall voltage is V_H^A. (B) If domains jump leaving domain B between the contacts C1 and C2, the Hall voltage jumps abruptly to V_H^B, whereas there is little change in the longitudinal resistance measured between the contacts C1 and C3. (C) The domain size is smaller by a factor N_W than the strip width W and by a factor N_L than the length L from C1 to C3. (D) Switching of a single domain causes a jump in ρ_H roughly proportional to 1/N_W, whereas in ρ it is on the order of 1/(N_LN_W) so it can be much smaller.