Sony Corporation

Ricoh Company, Ltd.

Toshiro Yamada

Yoshikazu Murakami

Seigo Ito

Hitoshi Tamada

Hideo Tanaka

Masami Miyake

Masahiko Kaneko

Yoshimi Makino

Kenichi Nakade

Tsutomu Okamoto

Masami Himuro

Whiteboard and photocopier

Disclosed is a YIG thin film device utilizing ferrimagnetic resonance effect, a magnetic circuit having a gap of length lg where the YIG thin film device being provided and applying a bias magnetic field perpendicular to a film surface of the YIG thin film device, the magnetic circuit including a permanent magnet having a thickness lm and a soft magnetic plate having a thickness lx, the permanent magnet satisfying the characteristics ##EQU1## the soft magnetic plate satisfying the characteristics ##EQU2## wherein fo is resonance frequency of the YIG thin film device,

YIG thin film microwave apparatus

A YIG film microwave device utilizing the ferrimagnetic resonance of a YIG film, comprising a YIG film microwave element formed by a liquid phase epitaxial growth process and a photolithographic process, and a magnetic circuit including permanent magnets for applying a DC magnetic field to the YIG film microwave element. Some of the Fe.sup.3+ ions of the YIG film are substituted by nonmagnetic ions to provide the YIG film microwave device with satisfactory temperature characteristics. The YIG film microwave device is capable of operating stably over the wide range of working frequency and that of temperature.

A signal converter comprises a filter formed of a first ferromagnetic resonator which supplied with an input signal that is to be converted and produces a filtered signal having a first frequency, a local oscillator formed of an active element and a second ferromagnetic resonator connected to the active element, produces an oscillating signal having a second frequency, a mixer receives and mixes the filtered signal and oscillating signal and produces a converted signal, the first ferromagnetic resonator is formed of a first ferrimagnetic crystal, a microstrip line magnetically coupled to the ferrimagnetic crystal and a first D.C. bias magnetic field means which applies a first D.C. bias magnetic field to the first ferrimagnetic crystal, the second ferromagnetic resonator is formed of a second ferrimagnetic crystal, a second microstrip line is magnetically coupled to the second ferrimagnetic crystal, and a second D.C. bias magnetic field means which applies a second D.C. bias magnetic field to the second ferrimagnetic crystal. The first and second ferrimagnetic crystals are composed of ferrimagnetic thin films such as YIG film formed by a thin film forming technique, such as liquid phase epitaxial growth.

Receiving circuit for converting signals comprising at least two

Thermomagnetic recording system

A tuned oscillator is disclosed which comprises an active element, a resonator electrically connected to the active element and made of a magnetic material using ferro-magnetic resonance phenomenon, and a magnetic circuit for applying a magnetic field to the resonator. The resonator is made of an YIG (yttrium, iron and garnet) thin film magnetic resonance element formed by a thin film forming technique and utilizes an uniform mode ferro-magnetic resonance in the YIG thin film, and operating under the application of magnetic field of the magnetic circuit.

YIG thin film tuned MIC oscillator

A pick-up device for reading out information which has been recorded on a magnetic medium. The device comprises a substrate and a layer of soft magnetic material overlying a surface of the substrate, the easy axis or direction of magnetization being normal to the surface and the magnetic material having properties capable of having magnetic bubble domains generated and propagated therein, so that when the pick-up device is used to read out information from a magnetic medium, patterns of magnetic domains are formed in the layer of magnetic material corresponding to the patterns of the recorded information. Although the magnetic material is of the type capable of having magnetic bubble domains generated and propagated therein, there is no need to provide the usual bias field for maintaining the bubble domains or for providing domain-transport or domain-annihilating fields. In one use of the pick-up device, light is transmitted through the substrate and through the layer of magnetic material to be reflected from a layer of light-reflective material back through the magnetic material and the substrate, whereby the polarization of the reflected light is rotated, relative to the polarization of the transmitted light, by an amount determined by the patterns of magnetic domains formed in the layer of magnetic material. Hence, the recorded information can be optically read from the magnetic medium. In another use of this device, a magnetoresistive head is disposed on the substrate, the resistance of this magnetoresistive head being varied as a function of the patterns of magnetic domains formed in the layer of magnetic material.

Growing community of inventors

Kanagawa, Japan

Toshiro Yamada