Abstract: Provided are a magnetic random access memory (MRAM) device using perpendicular magnetization, capable of stably reducing a size of a magnetic domain, and a method of fabricating the magnetic random access memory device. The magnetic random access memory device includes at least two magnetic layers, a tunnel insulation layer, and an underlayer. Each of the two magnetic layers has a magnetic domain perpendicularly magnetized in a thickness direction. The magnetic random access memory device includes an underlayer located on one side of at least one magnetic layer, and including at least one element of elements forming at least one magnetic layer to induce exchange coupling with the magnetic layer.

Abstract: Provided is a small form factor optical/magnetic disk including an integrated metal hub and a disk plate. The integrated metal hub includes a circular upper metal hub and a circular lower metal hub integrally formed with and disposed under the upper metal hub. The circular lower metal hub has a smaller diameter smaller than the upper metal hub. A central hole is formed in central portions of the upper and lower metal hubs and passes through the upper and lower metal hubs. The disk plate has a through-hole that is formed in a central portion and is directly associated with the integrated metal hub, and a recess that is formed around the through-hole and allows the upper metal hub to be mounted therein. Since the central portion of the small form factor optical/magnetic disk is not thick, the small form factor optical/magnetic disk can contribute to an ultra thin small form factor information storage device. Also, since manufacturing processes are simple, price and quality competitiveness can be enhanced.

Abstract: An ultra-small optical/magnetic head actuator includes: a swing arm movable in a horizontal direction (tracking direction) and a vertical direction (focusing direction) and having mounted thereon a head for reading and writing information on a disk. A tracking actuator moves the swing arm in the horizontal direction (tracking direction) and a pivot hinge adjusts a radius of rotation of the swing arm and guides the movement of the swing arm in the tracking direction. A focusing actuator moves the swing arm in the vertical direction (focusing direction), wherein the focusing actuator includes a focusing coil attached under the swing arm and a Halbach magnet array disposed under the focusing coil minimizes thickness. Friction or backlash can be avoided, and non-repetitive errors can be reduced. The thickness of the ultra-small storage device can be reduced due to the use of a Halbach magnet array.

Abstract: Provided are a jig used in a forming a cover layer of a small form factor optical disk and a method forming a cover layer in a small form factor optical disk using the jig. The jig includes: a body; a cylindrical wall formed inside the body and mounting an optical disk plate to a predetermined depth; and a pin positioned in a center of the cylindrical wall and combined with a central hole of the optical disk plate.

Abstract: An optical head has a beam input/output coupler on a planar waveguide and other parts including: a light transmitting element emitting a beam; a planar waveguide formed on a substrate and receiving the beam oscillated from the light transmitting element; a beam input/output coupler integrated as a thin film on a portion of the planar waveguide and receiving the beam through the planar waveguide to transmit the beam vertically toward a disc positioned above the planar waveguide or transmitting the beam reflected from the disc through the planar waveguide; and light receiving elements receiving the beam propagated to the planar waveguide through the beam input/output coupler.

Abstract: Provided is a method of manufacturing a form factor disk such as an optical or magnetic disk for use in electronic appliances and information appliances. The method includes forming a hub for readily mounting the disk to a magnetic rotational disk connected to a spindle motor of the information appliances by depositing or plating a magnetic material, whereby it is possible to minimize a thickness of the disk, simplifying a manufacturing process, allowing an ultra-small and ultra-slim form factor disk to be manufactured, and therefore, facilitating ultra-minimization and ultra-slim of the information appliances.

Abstract: Provided is a form factor disk such as an optical or magnetic disk used in electronic appliances and information appliances. The form factor disk includes: a circular plate having a first hole for inserting a rotational shaft, a plurality of second holes formed adjacent to the first hole, and an information storage region formed at a surface thereof; an upper metal hub located on the circular plate, and having a hole aligned with the first hole of the circular plate and column-shaped joints formed at portions corresponding to the second holes of the circular plate; and a lower metal hub located under the circular plate, and having a hole aligned with the first hole of the circular plate and column-shaped joints formed at portions corresponding to the second holes of the circular plate, wherein the joints of the upper and lower metal hubs are jointed through the second holes.

Abstract: Provided is an apparatus and method of initializing a recording layer used in manufacturing a phase-change optical disk for storing information. The optical disk is initialized using a UV lamp in order to initialize the recording layer of the phase-change optical disk capable of repeatedly writing information, without a separate optical head, whereby it is possible to increase productivity by remarkably reducing an initialization time of the optical disk since a large area is initialized using a UV beam.

Abstract: Provided is a planar focusing grating coupler, comprising: a light waveguide including a cladding layer and a core layer formed on a substrate and maintaining incident laser light in a single mode; and a focusing grating coupler formed to have a predetermined grating pitch at a certain area over the core layer, wherein the light using to the light waveguide forms a focal point with the grating layer in the direction perpendicular to the focusing grating coupler, whereby an ultra small pickup head for a mobile optical disk can be used.

Abstract: Provided are a stamper fabricated by using an embossing master and a focusing grating coupler fabricated by using the stamper, which is applicable to a subminiature pickup head for a mobile optic disk, whereby it is possible to reduce a weight and a volume of the pickup head with a simple process and low cost and to apply for mass production.

Abstract: A leaky plasmon mode directional coupler and a polarization detection module for a magneto-optical pickup head, which uses the leaky plasmon mode directional coupler, are provided. The leaky plasmon mode directional coupler is manufactured by integrating a planar waveguide and a leaky plasmon mode waveguide, which share a cladding layer with each other, into one body. The polarization detection module includes the leaky plasmon mode directional coupler, a first photo diode, which is formed on the leaky plasmon mode directional coupler, and a second photo diode, which is located at an output port of the planar waveguide.