▎ 摘　　要

NOVELTY - The detector comprises a substrate and a grid electrode and at least a pair of source electrode and a drain electrode set on the substrate. The source electrode and drain electrode form a conductive channel, where the conductive channel is graphene. The conductive channel is covered with a protein film protective layer. The protein film protective layer is connected with a magnetic induction protein. USE - Used as magnetic field detector. ADVANTAGE - The detector: has miniaturization, digitization, and integration; enhances response of amplified biological magnetic induction protein to the magnetic field excitation signal; realizes the mapping between the magnetic induction proteins and magnetic field intensity by data acquisition system with high sampling rate and multi-bit resolution; has higher conductive performance; and utilizes conductive channel to detect the charge transfer of the induction protein in response to magnetic field, so as to improve the sensitivity of detector. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a preparation method of magnetic field detector. DESCRIPTION OF DRAWING(S) - The drawing shows a structural diagram of the magnetic field detector.