Magnetic flux density-determined oriented attachment growth of FePt nanowires

Operating the oriented attachment growth (OA-growth) of crystals is one of the key approaches to fabricating one-dimensional nanostructures with excellent performance. A high magnetic field was employed to synthesize FePt nanowires (NWs), and a magnetic flux density (MFD) determined OA-growth is presented. Without a magnetic field, the primary shorter FePt NWs are created in a surfactant-formed “capsule” and only a small amount of them will connect to form longer NWs. A lower MFD only facilitates the connection between already connected longer NWs and primary short NWs, which increases the connection times of OA-growth. On increasing the MFD, the magnetic dipole–dipole energy factor of the primary shorter NWs will be raised to higher than 10−1, and the magnetic energy differences between the radial and axial of these NWs will also be enhanced. The connection and rotation of shorter FePt NWs are facilitated by the high MFD, which is due to the increasing connection times and probability of OA-growth. This indicates that tuning the magnitude of the MFD is an effective strategy for operating the OA-growth of NWs by controlling the rotation and connection.