Frozen‐In Magnetic Order in Uniaxial Magnetic Gels: Preparation and Physical Properties

We describe the preparation and characterization of uniaxial magnetic gels. Fibril formation of the embedded magnetic particles generates easily detectable magnetic and optical anisotropies. A finite magnetization is frozen‐in and leads to a ferromagnetic‐like response in small homogeneous external magnetic fields. We present, for the first time, frequency dependent measurements of the shear modulus G ′. Despite their optical and magnetic anisotropy, the gels are mechanically isotropic. The time‐dependent G ′ for a ferrogel in the parallel orientation in a homogeneous field of 200 mT. magnified image The time‐dependent G ′ for a ferrogel in the parallel orientation in a homogeneous field of 200 mT.