Provided herein are methods and compositions comprising a non-toxic ferromagnetic ink composition. Also provided herein are plastic objects containing a surface coating of a food-safe ferromagnetic ink composition. The coating imparts functionality to a plastic object such that the object is capable of being mechanically separated from waste stream using a commercial magnetic separator. The food-safe ink composition, which can be printed using high-speed flexographic, intaglio, offset printing or pad printing, combined with heat transfer printing or hot foil stamping consists of an ingestible magnetically susceptible pigment capable of rendering the printed template with magnetically active properties. The surface of the plastic object described can consist of geometric designs which increase printable surface area without significant changes in dimensions of the said object.

An apparatus and methods to make a product using supersonic cold-spray deposition of brittle functional materials in fine and micro features down to 10 μm in minimum dimension. The process may use semiconductors such as bismuth and antimony telluride formulations, and hard magnetic materials such as neodymium iron boride and strontium ferrite, and soft magnetic materials such as manganese zinc ferrite, and manganese ferrite materials. In addition, the methods and processes have been demonstrated for materials as soft as graphite and as hard as boron carbide. Micro components have been deposited in square, tapered and elongated shaped features with feature sizes as small as 10 μm in minimum dimensions and applied to flat and highly complex shaped surfaces. This process when combined with other cold spray manufacturing processes allows the total additive manufacturing of complete electronic, magnetic and other complex devices including multiple type of brittle functional materials.

An apparatus and methods to make a product using supersonic cold-spray deposition of brittle functional materials in fine and micro features down to 10 μm in minimum dimension. The process may use semiconductors such as bismuth and antimony telluride formulations, and hard magnetic materials such as neodymium iron boride and strontium ferrite, and soft magnetic materials such as manganese zinc ferrite, and manganese ferrite materials. In addition, the methods and processes have been demonstrated for materials as soft as graphite and as hard as boron carbide. Micro components have been deposited in square, tapered and elongated shaped features with feature sizes as small as 10 μm in minimum dimensions and applied to flat and highly complex shaped surfaces. This process when combined with other cold spray manufacturing processes allows the total additive manufacturing of complete electronic, magnetic and other complex devices including multiple type of brittle functional materials.

A method for manufacturing a device having a three-dimensional magnetic structure includes applying or introducing magnetic particles onto or into a carrier element. A plurality of at least partly interconnected cavities are formed between the magnetic particles, which contact one another at points of contact, by coating the arrangement of magnetic particles and the carrier. The cavities are penetrated at least partly by the layer generated when coating, resulting in the three-dimensional magnetic structure. A conductor loop arrangement is provided on the carrier or a further carrier. When a current flows through the conductor loop, an inductance of the conductor loop is changed by the three-dimensional magnetic structure, or a force acts on the three-dimensional magnetic structure or the conductor loop by a magnetic field caused by the current flow, or when the position of the three-dimensional magnetic structure is changed, a current flow is induced through the conductor loop.

A method for manufacturing a device having a three-dimensional magnetic structure includes applying or introducing magnetic particles onto or into a carrier element. A plurality of at least partly interconnected cavities are formed between the magnetic particles, which contact one another at points of contact, by coating the arrangement of magnetic particles and the carrier. The cavities are penetrated at least partly by the layer generated when coating, resulting in the three-dimensional magnetic structure. A conductor loop arrangement is provided on the carrier or a further carrier. When a current flows through the conductor loop, an inductance of the conductor loop is changed by the three-dimensional magnetic structure, or a force acts on the three-dimensional magnetic structure or the conductor loop by a magnetic field caused by the current flow, or when the position of the three-dimensional magnetic structure is changed, a current flow is induced through the conductor loop.

A stretchable sensor includes a stretchable layer including an elastomer, and a conductive layer at least partially buried in the stretchable layer and including a conductive nanostructure. The stretchable layer includes a plurality of first regions including a ferromagnetic material buried in the elastomer, and a second region excluding the plurality of first regions.

Some variations provide a magnetically anisotropic structure comprising a magnetically anisotropic film on a substrate, wherein the magnetically anisotropic film contains a plurality of discrete magnetic hexaferrite particles, wherein the film is characterized by an average film thickness from 1 micron to 5 millimeters, and wherein the magnetically anisotropic film contains from 2 wt % to 75 wt % organic matter. Some variations provide a magnetically anisotropic structure comprising an out-of-plane magnetically anisotropic film on a substrate, wherein the magnetically anisotropic film contains a plurality of discrete magnetic hexaferrite particles, wherein the film is characterized by an average film thickness from 1 micron to 5 millimeters, and wherein the magnetically anisotropic film contains a concentration of hexaferrite particles of at least 40 vol %. The magnetically anisotropic structures are fabricated at low temperatures so that the magnetically anisotropic film may be monolithically integrated into an integrated-circuit fabrication process.

A magnetic sheet includes a sheet, line-shaped N first magnetic members arranged on the sheet and having magnetic properties, and line-shaped N second magnetic members arranged on the sheet and having magnetic properties, where N denotes the number of the first magnetic members and denotes the number of the second magnetic members.

A magnetic core comprises an anisotropic, composite material, which itself includes a matrix material (e.g., a dielectric, non-magnetic material, preferably a paramagnetic material), and magnetically aligned, ferromagnetic particles. The latter may for instance include micrometer- and/or nanometer-length scale particles. Such particles form chains of particles within the matrix material, wherein the chains form percolation paths of magnetic conduction. The paths extend along a first direction, whereby the chains extend, each, substantially along this first direction, while being distinct and distant from each other along a second direction that is perpendicular to the first direction and, possibly, to a third direction that is perpendicular to both the first direction and the second direction. Necking bridges are preferably formed between the particles. Related devices (e.g., inductor, amplifiers, transformers, etc.) and fabrication methods are also disclosed.

The invention relates to the field of the protection of security documents such as for example banknotes and identity documents against counterfeit and illegal reproduction. In particular, the present invention provides processes for optical effect layers (OEL) exhibiting one or more indicia using a magnetic assembly comprising i) a soft magnetic plate (x31) comprising a) one or more voids (V) and b) one or more dipole magnets (x32-a), wherein the one or more dipole magnets (x32-a) are disposed within the one or more voids (V) and/or are facing said one or more voids (V), and/or one or more pairs of two dipole magnets (x32-b), wherein the dipole magnets (x32-b) of the one or more pairs are disposed below the soft magnetic plate (x31) and are spaced apart from the one or more voids (V).