Anisotropic α‐Fe 2 O 3 @TiO 2 Core–Shell Nanoparticles and Their Smart Electrorheological Response

α‐Fe 2 O 3 @TiO 2 core–shell nanoparticles were prepared through a combination of reflux and hydrolysis methods. Firstly, a spindle‐like and monodispersed α‐Fe 2 O 3 nanorod core was fabricated by using a reflux method. In the second step, an amorphous TiO 2 shell was coated onto the surface of the nonspherical α‐Fe 2 O 3 core with a uniform thickness by means of a controlled hydrolysis method. The morphology, structure, and electrorheological (ER) activity of α‐Fe 2 O 3 @TiO 2 core–shell nanoparticles were determined by X‐ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), magnetic testing, and by using a rotational rheometer. The resulting nonspherical core–shell nanoparticles possess the advantages of uniform sizes, weak magnetism, and smart electrorheological behavior. An enhanced ER effect is found with the α‐Fe 2 O 3 @TiO 2 and hollow TiO 2 ER suspension compared with that of a pure α‐Fe 2 O 3 ER suspension.