Anomalous Hall effect sensors based on magnetic element doped topological insulator thin films

Anomalous Hall effect (AHE) is recently discovered in magnetic element doped topological insulators (TIs), which promises low power consumption highly efficient spintronics and electronics. This discovery broaden the family of Hall effect (HE) sensors. In this work, both HE and AHE sensor based on Mn and Cr doped Bi$_{\mathrm{2}}$Te$_{\mathrm{3}}$ TI thin films will be systematically studied. The influence of Mn concentration on sensitivity of Mn$_{\mathrm{x}}$Bi$_{\mathrm{2-x}}$Te$_{\mathrm{3}}$ HE sensors will be discussed. The Hall sensitivity increase 8 times caused by quantum AHE will be reported. AHE senor based on Cr-doped Bi$_{\mathrm{2}}$Te$_{\mathrm{3}}$ TI thin films will also be studied and compared with Mn doped Bi$_{\mathrm{2}}$Te$_{\mathrm{3}}$ AHE sensor. The influence of thickness on sensitivity of Cr$_{\mathrm{x}}$Bi$_{\mathrm{2-x}}$Te$_{\mathrm{3}}$ AHE sensors will be discussed. Ultrahigh Hall sensitivity is obtained in Cr doped Bi$_{\mathrm{2}}$Te$_{\mathrm{3}}$. The largest Hall sensitivity can reach 2620 $\Omega $/T in sensor which is almost twice higher than that of the normal semiconductor HE sensor. Our work indicates that magnetic element doped topological insulator with AHE are good candidates for ultra-sensitive Hall effect sensors.