Columnar CoFe2O4 thin films with improved magnetic properties via high magnetic field

•Columnar ordered arrayed CFO thin films are derived on silicon wafers within different magnetic fields.•The lateral size of CFO nanorod can be tunable by control the magnetic field.•Both the magnetization and coercivity of the CFO thin films are improved with applied high magnetic field. Columnar nanostructures or ordered nanoarrays of CoFe2O4 (CFO) thin films are desirable in applications. While, the difficulties in achieving large-area columnar CFO thin films with a tunable lateral size and a controllable height/length ratio have limited their applications as synthesizing heterostructures and composites. Herein, CFO thin films with vertically aligned nanorod structures from bottom to up have been achieved on silicon substrates by high magnetic field assisted pulsed laser deposition. Lateral size of the nanorod decreases with increasing the magnetic field. Moreover, both the coercivity and the magnetization at room temperature increase with increasing the magnetic field in deposition. These results will provide a feasible route to deposit large-area and technologically relevant to advance the applications of CFO thin films.