Some variations provide a magnetically anisotropic structure comprising a hexaferrite film disposed on a substrate, wherein the hexaferrite film contains a plurality of discrete and aligned magnetic hexaferrite particles, wherein the hexaferrite film is characterized by an average film thickness from about 1 micron to about 500 microns, and wherein the hexaferrite film contains less than 2 wt % organic matter. The hexaferrite film does not require a binder. Discrete particles are not sintered or annealed together because the maximum processing temperature to fabricate the structure is 500 C. or less, such as 250 C. or less. The magnetic hexaferrite particles may contain barium hexaferrite (BaFe.sub.12O.sub.19) and/or strontium hexaferrite (SrFe.sub.12O.sub.19). The hexaferrite film may be characterized by a remanence-to-saturation magnetization ratio of at least 0.7. Methods of making and using the magnetically anisotropic structure are also described.

A magnetic microcapsule, preparation method thereof and a magnetic film are disclosed, relating to microcapsule technology. The microcapsules use a combination of cationic and anionic polymers as the shell material, forming spindle-shaped, durable spheres to enhance strength. The core material contains at least two types of magnetic particles with different strengths, allowing adjustable magnetic forces to improve writing, erasure, and contrast. It also includes non-magnetic particles, an oil-based solvent, and a suspension stabilizer, forming a stable cross-linked network and electrostatic adsorption layer to prevent sedimentation and ensure smooth writing and lasting marks. The resulting magnetic film offers excellent responsiveness, enabling quick and thorough erasure by adjusting the magnetic pen's force and frequency.

A magnetic microcapsule, preparation method thereof and a magnetic film are disclosed, relating to microcapsule technology. The microcapsules use a combination of cationic and anionic polymers as the shell material, forming spindle-shaped, durable spheres to enhance strength. The core material contains at least two types of magnetic particles with different strengths, allowing adjustable magnetic forces to improve writing, erasure, and contrast. It also includes non-magnetic particles, an oil-based solvent, and a suspension stabilizer, forming a stable cross-linked network and electrostatic adsorption layer to prevent sedimentation and ensure smooth writing and lasting marks. The resulting magnetic film offers excellent responsiveness, enabling quick and thorough erasure by adjusting the magnetic pen's force and frequency.

Provided herein are compositions comprising substrates that contain polymeric materials or non-magnetic, paramagnetic, or diamagnetic metal objects, and films or inks that contain ferromagnetic materials in which the films or the ferromagnetic materials are transparent. Also provided herein are methods of fabricating the substrates. Further provided herein are ferromagnetic material films containing transparent or translucent films that comprises ferromagnetic materials. The coating imparts functionality to the film such that the film is capable of being mechanically separated from the polymeric materials or non-magnetic, paramagnetic, or diamagnetic metal objects using a commercial magnetic separator. The transparent, food-safe ink composition, which can be printed using high-speed flexographic, gravure, intaglio, offset printing or pad printing consists of an ingestible magnetically susceptible pigment capable of rendering the printed template with magnetically active properties.

Provided herein are compositions comprising substrates that contain polymeric materials or non-magnetic, paramagnetic, or diamagnetic metal objects, and films or inks that contain ferromagnetic materials in which the films or the ferromagnetic materials are transparent. Also provided herein are methods of fabricating the substrates. Further provided herein are ferromagnetic material films containing transparent or translucent films that comprises ferromagnetic materials. The coating imparts functionality to the film such that the film is capable of being mechanically separated from the polymeric materials or non-magnetic, paramagnetic, or diamagnetic metal objects using a commercial magnetic separator. The transparent, food-safe ink composition, which can be printed using high-speed flexographic, gravure, intaglio, offset printing or pad printing consists of an ingestible magnetically susceptible pigment capable of rendering the printed template with magnetically active properties.