Anomalous Hall effect in Fe/Gd bilayers

Abstract

Non-monotonic dependence of anomalous Hall resistivity on temperature and magnetization, including a sign change, was observed in Fe/Gd bilayers. To understand the intriguing observations, we fabricated the Fe/Gd bilayers and single layers of Fe and Gd simultaneously. The temperature and field dependences of longitudinal resistivity, Hall resistivity and magnetization in these films have also been carefully measured. The analysis of these data reveals that these intriguing features are due to the opposite signs of Hall resistivity/or spin polarization and different Curie temperatures of Fe and Gd singlelayer films. PACS. 72.15.Gd, 73.61.-r, 75.70.-i * Xixiang.Zhang@kaust.edu.sa

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“…For inhomogeneous granular and multilayer samples, spin-dependent interfacial scattering leads to large γ (>2), e.g., γ = 2.6 in Fe/Cr multilayers [13] and γ = 3.7 in Co-Ag granular thin films [14], which cannot be ascribed to any of the three mechanisms above. Moreover, in the multilayer heterostructures, the shunting effect is a critical issue in Hall resistivity measurement [15][16][17]. Because the Hall voltage depends on the current flow in each layer, the conventional bulk scaling law cannot be applied for samples with different current distributions.…”

Rashba-Edelstein Magnetoresistance in Metallic Heterostructures

“…Thus, with these assumptions, the Bi/Ag/CoFeB trilayer can be modeled as four independent resistors in parallel: the Bi, Ag, CoFeB, and Bi/Ag interface layers. By taking into account the shunting and short-circuit effects [33, 48,49], we obtain…”

Anomalous Hall effect in Co40Fe40B20/SiO2/Si structures

“…Furthermore, the effect of carriers transporting between FM and Si on the AHE has been neglected. No-monotonic dependence of AHE resistivity on temperature was found in Fe/Gd bilayers [15]. The AHE was found not to follow the scaling law derived from skew scattering or side jump M A N U S C R I P T…”

“…Such unconventional phenomena arise from the carriers transporting between Fe and Gd (Cu) layers [15,16] where R AH =4πχR s , χ is magnetic susceptibility, R s is anomalous Hall coefficient and R 0 is the ordinary Hall coefficient of Si. With the increase of temperature, the magnitude of R AH I CoFeB drops rapidly, however, which is still larger than R 0 I Si .…”