Northeastern University

USA As Represented by Secretary of the Navy

Rogers Corporation

Metamagnetics, Inc.

Vincent G Harris

Yajie Chen

Alan Shane Edelstein

Carmine Vittoria

Forrest H Kaatz

Anton L Geiler

Parisa Andalib

Everett Earl Carpenter

Zhaohui Chen

Francesca Scire Scappuzzo

Shannon A Morrison

Magnetodielectric (MD) metamaterials have a magnetodielectric (MD) substrate of a ferrite composition or composite having a characteristic impedance matching an impedance of free space and at least one frequency selective surface (FSS). The FSS has a plurality of frequency selective surface elements disposed in a pattern and supported on the MD substrate. The FSS has a conducting composition and is configured to permit one or more of transmission, reflection, or absorption at a selected resonant frequency or selected frequency band. Articles incorporating magnetodielectric metamaterials are provided.

Magnetodielectric metamaterials and articles including magnetodielectric metamaterials

A composite magnetic material has a plurality of grains having a magnetic ferrite phase, grain boundaries surrounding the grains, and a plurality of nanoparticles disposed at the grain boundaries. The nanoparticles of the composite material are both magnetic and electrically insulating, having a magnetic flux density of greater than about 100 mT and an electrical resistivity of at least about 10Ohm-cm. Also provided is a method of making the composite material. The material is useful for making inductor cores of electronic devices.

Magnetic materials with ultrahigh resistivity intergrain nanoparticles

A CoZ hexaferrite composition is provided containing molybdenum and one or both of barium and strontium, having the formula (BaSrCo)MoFeOwhere x=0.01 to 0.20; y=20 to 24; and z=0 to 3. The composition can exhibit high permeabilities and equal or substantially equal values of permeability and permittivity while retaining low magnetic and dielectric loss tangents and loss factors. The composition is suitable for high frequency applications such as ultrahigh frequency and microwave antennas and other devices.

Mo-doped CoZ-type ferrite composite material for use ultra-high frequency antennas

A ferrite composition is provided containing Ba, Co, and Ir and having a Z-type hexaferrite phase and a Y-type hexaferrite phase. The ferrite composition has the formula BaCoIrFeOwhere x=0.05-0.20. The composition has equal or substantially equal values of permeability and permittivity while retaining low magnetic and dielectric loss factors. The composition is suitable for ultrahigh frequency applications such as high frequency and microwave antennas.

Co2 Z-type ferrite composite material for use in ultra-high frequency antennas

Devices and methods for directing a magnetic field into a body party of a subject are provided. The devices include at least one electromagnetic coil, a magnetic core or yoke, and a pair of flux concentrators. The flux concentrators are separated by a gap into which the body part fits and through which the flux concentrators focus the magnetic field. The devices allow magnetic fields to be transmitted through the gap with higher intensity at greater distances from the device than possible with previous designs. The methods of using such devices allow the delivery of magnetic fields with higher intensity to the interior of a body part without exposing interposed proximal regions to magnetic fields of unduly high intensity. The devices and methods are useful for deep transcranial magnetic stimulation of the brain to treat various medical conditions.

Device and method for deep transcranial magnetic stimulation

Tunable microwave magnetic devices that provide increased performance with reduced size, weight, and cost. The disclosed microwave magnetic devices are voltage-tunable devices that include ferrite substrates. To tune the devices, the magnetic permeability of the respective ferrite substrates is varied by external, voltage-tuned, magnetic fringe fields created by one or more magnetoelectric (ME) transducers.

Voltage tuning of microwave magnetic devices using magnetoelectric transducers

A composite material can include a grain component and a nanostructured grain boundary component. The nanostructured grain boundary component can be insulating and magnetic, so as to provide greater continuity of magnetization of the composite material. The grain component can have an average grain size of about 0.5-50 micrometers. The grain boundary component can have an average grain size of about 1-100 nanometers. The nanostructured magnetic grain boundary material has a magnetic flux density of at least about 250 mT. The grain component can comprise MnZn ferrite particles. The nanostructured grain boundary component can comprise NiZn ferrite nanoparticles. Core components and systems thereof can be manufactured from the composite material.

Magnetic grain boundary engineered ferrite core materials

A composition of a crystalline ferromagnetic material based upon nanoscale cobalt carbide particles and to a method of manufacturing the ferromagnetic material of the invention via a polyol reaction are disclosed. The crystalline ferromagnetic cobalt carbide nanoparticles of the invention are useful for high performance permanent magnet applications. The processes according to the invention are extendable to other carbide phases, for example to Fe-, FeCo-carbides. Fe- and FeCo-carbides are realizable by using as precursor salts Fe-, Co-, and mixtures of Fe- and Co-salts, such as acetates, nitrates, chlorides, bromides, citrates, and sulfates, among others. The materials according to the invention include mixtures and/or admixtures of cobalt carbides, as both CoC and CoC phases. Mixtures may take the form of a collection of independent particles of CoC and CoC or as a collection of particles which consist of an intimate combination of CoC and CoC phases within individual particles. The relative proportions of these two phases as well as the morphology of each phase contribute to their attractive permanent magnet properties, particularly at low temperatures through room temperature and up to over 400 K.

Cobalt carbide-based nanoparticle permanent magnet materials

A broadband integrated circulator antenna (BICA) module for receiving and transmitting signals with high efficiency and high gain. The BICA can have a bandwidth of over 70% of a radar band and can operate in frequencies from UHF to S-band and above. The BICA has a stack configuration that includes a low profile antenna, a reflecting layer or a metamaterial substrate layer, and a circulator. The circulator is placed proximal to antenna, which greatly reduces the size of the BICA. The circulator can be a stripline Y-junction ferrite circulator and the antenna can be a coaxial center fed bow-tie antenna. The reflecting layer or metamaterial substrate layer can comprise electronic bandgap metamaterial and a high permeability ferrite substrate. The high permeability ferrite substrate can be cobalt substituted Z-type barium hexaferrite.

Antenna module having reduced size, high gain, and increased power efficiency

A semiconductor device including a ferrite layer, a widebandgap semiconductor material layer, and a buffer layer. The buffer layer comprises an interweaving of MgO and BaM. In addition the buffer layer allows a gradual reduction of the interfacial stress, and mediates the strain between a silicon substrate and a ferrite layer of the device. In addition, the buffer layer allows for high crystal alignment resulting in high crystal quality and thereby producing a low microwave loss semiconductor device. The buffer layer also minimizes chemical interdiffusion of atoms between the substrate and the ferrite layer.

Growth of high quality low-loss ferrite materials on wide bandgap semiconductor substrates

A method for making monodispersed magnetic nanoparticles of nickel zinc ferrite (NZFO) at room temperature by mixing together two micelle solutions. The first micelle solution comprises zinc, nickel, and iron metal salts; a surfactant; and a hydrocarbon. The second micelle solution comprises an aqueous hydroxide, a surfactant, and a hydrocarbon. After mixing the two micelle solutions, the ferrite precipitates.

Nanoparticle nickel zinc ferrites synthesized using reverse micelles

Nanoparticles of a mixed oxide precursor are reduced to form particles of a anostructured metastable alloy having a majority metal and a minority metal. Additional heating enriches the surfaces of the particles with respect to the minority metal, thus forming a coating on the particle core. This coating has a higher atomic ratio of minority to majority metal than found in the precursor. The nanostructured metastable alloys may then be oxidized to form nanoparticles having a coating of the oxide of the minority metal and a core of the majority metal or an oxide of the majority metal. The majority metal may be, for example, copper. The minority metal may be, for example, cobalt.

Method of making chemically engineered metastable alloys and multiple

Oxidation resistant particles composed of copper and at least one metal hng a valence of +2 or +3 and having an intermediate lattice energy for the metal in its hydroxide form. The metal is selected from nickel, cobalt, iron, manganese, cadmium, zinc, tin, magnesium, calcium and chromium. In one embodiment, the phases of copper and at least one metal in the particles are separate and the concentration of the metal is greater near the surface of the particles than inwardly thereof. Process for making the oxidation resistant copper particles includes the steps of dissolving a copper salt and a salt of at least one of the metals in a suitable solvent or diluent; forming primary particles of copper and at least one metal in basic form by mixing a base and the salt solution; separating, washing and drying the primary particles; reducing the primary particles to metallic form; and heat treating the particles in metallic form at an elevated temperature.

Oxidation resistant copper

Oxidation resistant particles composed of copper and at least one metal having a valence of +2 or +3 and having an intermediate lattice energy for the metal in its hydroxide form. The metal is selected from nickel, cobalt, iron, manganese, cadmium, zinc, tin, magnesium, calcium and chromium. In one embodiment, the phases of copper and at least one metal in the particles are separate and the concentration of the metal is greater near the surface of the particles than inwardly thereof. Process for making the oxidation resistant copper particles includes the steps of dissolving a copper salt and a salt of at least one of the metals in a suitable solvent or diluent; forming primary particles of copper and at least one metal in basic form by mixing a base and the salt solution; separating, washing and drying the primary particles; reducing the primary particles to metallic form; and heat treating the particles in metallic form at an elevated temperature.

Growing community of inventors

Beltsville, MD, United States of America

Vincent G Harris