Ultra-sensitive anomalous Hall effect sensors based on Cr-doped Bi₂Te₃ topological insulator thin films

The observation of anomalous Hall effect (AHE) in magnetically doped topological insulators brings a new candidate of Hall sensor with low power consumption. In this work, the transport properties and the sensitivity of AHE sensors based on Cr-doped Bi₂Te₃ thin films were studied. Obvious AHEs induced by ferromagnetic ordering were presented in all Cr_xBi_2-xTe₃ sensors. At the optimized doping concentration of x= 0.09, a high sensitivity of 6625 Ω T⁻¹ was achieved, which has increased by 2.5 times compared to the highest reported one in Cr-doped Bi₂Te₃. More importantly, a considerable sensitivity of 4082 Ω T⁻¹ can be obtained up to 20 K, which implies a higher working temperature than other reports. Our findings suggest Cr-doped Bi₂Te₃ sensor could be a good candidate for highly sensitive AHE sensors and reveal the extraordinary potential of magnetic TIs in the applications of field detection. (paper)