Scaling of the Hall effects beyond the quantum resistance threshold in oxidized CoFeB

Abstract

The ordinary and the extraordinary Hall effects were studied in gradually oxidized amorphous CoFeB ferromagnets over six orders of resistivity from the metallic to the strongly insulating regime. Polarity of the extraordinary Hall effect reverses, and the amplitude of both the ordinary and the extraordinary Hall effects increases quadratically with resistivity when resistance exceeds the quantum resistance threshold. The absolute value of the extraordinary Hall effect scales linearly with the ordinary one in the entire range over eight orders of magnitude between the metallic and the insulating states. The behavior differs qualitatively and quantitatively from theoretically predicted and experimentally known in other materials.

References in corpus (6)

• Intrinsic vs. extrinsic anomalous Hall effect in ferromagnets
• Quantum transport theory of anomalous electric, thermoelectric, and thermal Hall effects in ferromagnets
• Hall resistivity of granular metals
• Hall Transport in Granular Metals and Effects of Coulomb Interactions
• Absence of the Ordinary and Extraordinary Hall effects scaling in granular ferromagnets at metal-insulator transition
• MegaOhm Extraordinary Hall effect in oxidized CoFeB