We demonstrate that a distinct high-disorder anomalous Hall effect phase emerges at the correlated insulator threshold of ultrathin, amorphous, ferromagnetic CNi3 films. In the weak-localization regime, where the sheet conductance G e2/h, the anomalous Hall resistance of the films increases with increasing disorder and the Hall conductance scales as Gxy Gφ with φ=1.6. However, at sufficiently high disorder the system begins to enter the 2D correlated insulator regime, at which point the Hall resistance Rxy abruptly saturates and the scaling exponent becomes φ=2. Tunneling measurements show that the saturation behavior is commensurate with the emergence of the 2D Coulomb gap, suggesting that e-e interactions mediate the high-disorder phase. © 2010 The American Physical Society.
Publication Source (Journal or Book title)
Physical Review Letters
Xiong, Y., Adams, P., & Catelani, G. (2010). Saturation of the anomalous hall effect in critically disordered ultrathin CNi3 films. Physical Review Letters, 104 (7) https://doi.org/10.1103/PhysRevLett.104.076806