Details

Autor(en) / Beteiligte

• Hazra, Binoy Krishna
• Kaul, S.N.
• Srinath, S.
• Raja, M. Manivel
• Rawat, R.
• Lakhani, Archana

Titel

Diffuson contribution to anomalous Hall effect in disordered Co2FeSi thin films

Ist Teil von

• Journal of magnetism and magnetic materials, 2019-07, Vol.481, p.194-202

Ort / Verlag

Amsterdam: Elsevier B.V

Erscheinungsjahr

2019

Link zum Volltext

Quelle

Elsevier ScienceDirect Journals Complete

Beschreibungen/Notizen

• •Discovery of electron-diffuson scattering contribution to anomalous Hall effect (AHE).•Only in disordered ferromagnets (FMs) does the weak localization contribute to AHE.•Electron-electron interaction effects do not contribute to AHE in crystalline FMs.•A universal scaling holds between AHE and temperature-dependent part of resistivity. An exhaustive study of the influence of disorder on anomalous Hall (AH) resistivity (ρxyAH), longitudinal resistivity (ρxx), magnetoresistance and magnetization of Co2FeSi (CFS) Heusler alloy thin films of fixed (50 nm) thickness, deposited on Si (111) substrate, reveals the following. Regardless of the degree of disorder present, the side-jump mechanism gives a dominant contribution to ρxyAH. A new and novel contribution to both ρxx and ρxyAH, characterized by the logarithmic temperature (-lnT) dependence at temperatures below the minimum (T<Tmin), exclusive to the amorphous CFS films, originates from the scattering of conduction electrons from the diffusive hydrodynamic modes associated with the longitudinal component of magnetization, called ‘diffusons’. The electron-diffuson, e-d, scattering and weak localization (WL) mechanisms compete with the inelastic electron-magnon, e-m, scattering to produce the minimum in ρxx(T), whereas the minimum in ρxyAH(T) is caused by the competing contributions from the e-d and e-m scattering, as WL does not contribute to ρxyAH. Another novel finding is that the e-d scattering contributions to ρxyAH(T) and ρxx(T)scale with each other. In sharp contrast, in crystalline films, enhanced electron-electron Coulomb interaction (EEI), which is basically responsible for the resistivity minimum, does not contribute to ρxyAH with the result that no minimum in ρxyAH(T) is observed. The conventional ρxyAH = f(ρxx) scaling breaks down completely in the present case. However, when ρxyAH(T) is corrected for the e-d contribution and ρxx(T) for both e-d and WL contributions (only EEI) in the amorphous (crystalline) films, the AH coefficient, RA(T) = ρxyAH(T) / 4πMs(T), (calculated from the correctedρxyAH and spontaneous magnetization, Ms), perfectly scales with ρxxT, the temperature-dependent part of the correctedρxx, for all the CFS thin films.