Giant Planar Hall Effect in Epitaxial (Ga,Mn)As Devices
  Large Hall resistance jumps are observed in microdevices patterned from epitaxial (Ga,Mn)As layers when subjected to a swept, in-plane magnetic field. This giant planar Hall effect is four orders of magnitude greater than previously observed in metallic ferromagnets. This enables extremely sensitive measurements of the angle-dependent magnetic properties of (Ga,Mn)As. The magnetic anisotropy fields deduced from these measurements are compared with theoretical predictions. 
H.X. Tang, R.K. Kawakami, D.D. Awschalom, and M.L. Roukes