Anomalous Hall effect in (Co$_{41}$Fe$_{39}$B$_{20})_ x$ (Al–O)$_{100 -x}$ nanocomposites

The concentration dependence of the coefficient $R_ s$ characterizing the anomalous Hall effect (AHE) has been studied by measuring the electrical resistivity $\rho$, magnetoresistance, and the magnetic field dependence of magnetization and Hall resistivity of (Co$_{41}$Fe$_{39}$B$_{20})_x$(Al–O)$_{1-x}$ nanocomposite thin films. It has been demonstrated that the AHE coefficient increases by more than an order of magnitude with a decrease in the percentage $x$ of the amorphous ferromagnetic metal from $60$ to $30$ and its behavior is described by the relation $R_s\sim\rho^m$, where $m=0.46\pm0.1$. At the same time, the coefficient characterizing the normal Hall effect grows by a factor of less than $10$. The mechanisms underlying the giant Hall effect in nanocomposites have been discussed.