A piezoelectric rotatable magnetic force microscope system in a 10 T cryogen-free superconducting magnet

We constructed a piezoelectric rotatable magnetic force microscope (MFM) that works in a 10 T cryogen-free superconducting magnet. The piezoelectric tube is deformed tangentially and drives a bearing under the inertial drive principle so the MFM head can obtain rotary movement. Due to the novel piezoelectric design, the MFM can be hung underneath the heat sink via a soft spring, and it can be rotated in a cryogen-free superconducting magnet so that the direction of the magnetic field can be changed from 0° to 90° continuously. The system functions in magnetic fields of up to 10 T in any direction relative to the tip-sample geometry. This is the first piezoelectric rotatable MFM ever reported. Using this homemade rotatable MFM, we imaged the structure of magnetic tracks on a commercial videotape. When the magnetic field angle changes from 0° to 90°, the magnetic moments on the tape and probe tip also rotate. A magnetic field strength of 0.8 T parallel to the sample surface is required to fully rotate the magnetic moment of the tip we used, but 0.8 T is not enough to fully rotate the magnetic moment of the sample. The piezoelectric rotatable MFM is expected to be widely used to study the anisotropy of magnetic materials due to its superiority in obtaining the same high field in and out of plane (compared with a vector magnet) as well as in maintaining the same scan area precisely (compared with a mechanical rotatable MFM, especially for atomic-scale scan areas).