Fujitsu Corporation

Nagoya Institute of Technology

Keiji Shono

Koji Matsumoto

Ken Tamanoi

Tsutomu Tanaka

Sumio Kuroda

Motonobu Mihara

Toshio Sugimoto

Hiroyasu Kawano

Yasunobu Hashimoto

Haruhiko Izumi

Mineo Moribe

Miyozo Maeda

Yuzuru Yamakage

Tomonori Ikeya

Takuya Kamimura

Yoshiyuki Namba

Manabu Gomi

Takeshi Yokota

A resistance variable element is provided, which is capable of performing bipolar operation by a specified mechanism and usable as a memory. The resistance variable element has a laminated structure including an electrode, another electrode, an oxide layer between the electrodes, and an oxide layer in contact with the oxide layer between the oxide layer and the electrode. The oxide layer is switchable from the low-resistance state to the high-resistance state by donating oxygen ions to the oxide layer, and from the high-resistance state to the low-resistance state by accepting oxygen ions from the oxide layer. The oxide layer is switchable from the low-resistance state to the high-resistance state by accepting oxygen ions from the oxide layer, and from the high-resistance state to the low-resistance state by donating oxygen ions to the oxide layer.

Resistance variable element

The invention provides a variable-resistance element having a multilayer structure. The variable-resistance element includes, for example, a first electrode, a second electrode, and an oxygen ion migration layer disposed between the first electrode and the second electrode. In the oxygen ion migration layer, oxygen vacancy can be produced owing to oxygen ion migration, thereby forming a low resistance path. The variable-resistance element also includes an oxygen ion generation promoting layer disposed between the oxygen ion migration layer and the first electrode and held in contact with the oxygen ion migration layer.

Variable-resistance element

The invention is a magneto-optical recording medium characterized by containing at least a soft magnetic layer, a protective layer, a resin layer having a servo pattern formed thereon, a reflecting film, a lower dielectric material film, a recording film, an upper dielectric material film, and a cover layer, formed on a substrate in this order.

Magneto-optical recording medium including a soft magnetic layer, a protective layer and a silane coupling agent layer, in this order

A magneto-optical recording medium capable of perfectly masking a mark adjacent to a mark to be reproduced thereby improvng reproduction output. The magneto-optical recording medium includes a transparent substrate, a magnetic reproducing layer laminated on the transparent substrate, a nonmagnetic intermediate layer laminated on the magnetic reproducing layer, and a magnetic recording layer laminated on the nonmagnetic intermediate layer. The reproducing layer has an easy direction of magnetization in a plane at room temperature, and has an easy direction of magnetization perpendicular to a film surface at a given temperature or higher. The nonmagnetic intermediate layer is thin enough to allow magnetostatic bond between the recording layer and the reproducing layer at the given temperature or higher. Instead of the nonmagnetic intermediate layer, a magnetic intermediate layer having an easy direction of magnetization in a plane from room temperature to its Curie temperature may be interposed between the reproducing layer and the recording layer.

Magneto-optical recording medium and reproducing method for information recorded on the medium

A magneto-optical recording medium capable of perfectly masking a mark adjacent to a mark to be reproduced thereby improving a reproduction output. The magneto-optical recording medium includes a transparent substrate, a magnetic reproducing layer laminated on the transparent substrate, a nonmagnetic intermediate layer laminated on the magnetic reproducing layer, and a magnetic recording layer laminated on the nonmagnetic intermediate layer. The reproducing layer has an easy direction of magnetization in a plane at room temperature, and has an easy direction of magnetization perpendicular to a film surface at a given temperature or higher. The nonmagnetic intermediate layer is thin enough to allow magnetostatic bond between the recording layer and the reproducing layer at the given temperature or higher. Instead of the nonmagnetic intermediate layer, a magnetic intermediate layer having an easy direction of magnetization in a plane from room temperature to its Curie temperature may be interposed between the reproducing layer and the recording layer.

Magneto-optical recording medium and reproducing method for information recorder on the medium

A magneto-optical recording medium composed of a plurality of magnetic layers including a rare earth metal and a transition metal as main components. The magneto-optical recording medium includes a magnetic reproducing layer having an easy axis of magnetization perpendicular to a film plane, and a magnetic control layer formed over the magnetic reproducing layer and having an easy axis of magnetization in a plane at a room temperature. A magnetic moment of the rare earth metal of the magnetic control layer being predominant over a magnetic moment of the transition metal of the magnetic control layer. The magnetic control layer includes at least Gd as the rare earth metal and Fe as the transition metal. The magneto-optical recording medium further includes a magnetic recording layer formed over the magnetic control layer and having an easy axis of magnetization perpendicular to the film plane. A Curie temperature Tc1 of the magnetic reproducing layer, a Curie temperature Tc2 of the magnetic control layer, and a Curie temperature Tc3 of the magnetic recording layer are related to satisfy Tc1&gt;Tc2 and Tc3&gt;Tc2. A coercive force Hc1 of the magnetic reproducing layer at the room temperature and a coercive force Hc3 of the magnetic recording layer at the room temperature are related to satisfy Hc3&gt;Hc1.

Magneto-optical recording medium and reproducing method for information

A magneto-optical recording medium of a three-layered structure (consisting of a readout layer, an intermediate layer, and a recording layer), capable of double-mask magnetically-induced super-resolution readout, has magnetic properties such that the exchange coupled force between the readout layer (a GdFeCo film) and the intermediate layer (a GdFe film) decrease with increasing temperature, while the exchange coupled force between the intermediate layer and the recording layer (a TbFeCo film) increase with increasing temperature. The magnetic property of the readout layer is transition-metal magnetization dominant, and that of the intermediate layer is rare-earth magnetization dominant. When reading the medium, a region (an intermediate-temperature transfer region) where the magnetization in the readout layer is oriented in the direction of magnetization in the recording layer, and a region (a high-temperature rear mask) where the magnetization in the readout layer is oriented in a second specific direction, are simultaneously formed within a beam spot from a state (a low-temperature front mask) in which the magnetization in the readout layer is oriented in a first specific direction, thus achieving a double mask condition in a single step. Overwrite recording and magnetically-induced super-resolution readout are realized on the same magneto-optical recording medium.

Magneto-optical recording medium capable of double mask readout

A magneto-optical recording medium, and a method of its production, a method of reading and an apparatus of reading the same capable of decreasing the magnetic field to be applied during MSR readout, or reading without applying magnetic field, by including first, second and third magnetic layers having specified magnetic characteristics.

Magneto-optical recording medium and method of producing the same

A magneto-optical recording medium capable of performing magnetically induced super resolution reproduction by perfectly masking a mark adjacent to a mark to be reproduced. The magneto-optical recording medium includes a transparent substrate, a magnetic reproducing layer laminated on the transparent substrate, a magnetic control layer laminated on the reproducing layer, and a magnetic recording layer laminated on the control layer. The reproducing layer has an easy axis of magnetization in a plane at room temperature. Each of the control layer and the recording layer has an easy axis of magnetization perpendicular to the substrate. When a given reproducing power is applied to the medium, there are formed in a laser spot on the medium a low-temperature area where the direction of magnetization of the reproducing layer is made identical with an in-plane direction, an intermediate-temperature area where the magnetization of the recording layer is transferred through the control layer to the reproducing layer by exchange bond, and a high-temperature area whose temperature is higher than the Curie temperature of the control layer. In the low-temperature area, an in-plane mask is formed. In the high-temperature area, an up spin mask is formed. Further, an opening allowing a magneto-optical signal to be read is formed between the two masks.

A magneto-optic disk has a readout layer formed of a bismuth-substituted garnet having a chemical composition represented by Bi.sub.x R.sub.3-x M.sub.y Fe.sub.5-y O.sub.12 and a recording layer formed of a nonbismuth-substituted garnet having a chemical composition represented by R.sub.3 M, Fe.sub.5-z O.sub.12 (where 0.ltoreq.x.ltoreq.3, 0.ltoreq.y&lt;2, 0.ltoreq.z&lt;2, R represents yttrium or a rare earth element, and M represents element which can be substituted for iron (Fe). The readout layer has a smaller coercive force and a higher Curie temperature in comparison with the recording layer, and exhibits a characteristic of a large angle of Faraday rotation 200 times that of the recording layer with respect to a short-wavelength laser beam of about 500 nm. Therefore, the MSR technique utilizing masking of the recording layer with the readout layer can be applied to this magneto-optic disk to achieve a high recording density about 16 times that in the case of a magneto-optic disk having an amorphous alloy thin film formed of a rare earth element and a transition metal and effective with respect to a laser beam of a comparatively long wavelength about 800 nm.

High-density magneto-optic disk and method of manufacturing the same

A magneto-optic recording medium with a transparent substrate, a first dielectric layer above the transparent substrate, a magnetic layer above the first dielectric layer, a second dielectric layer above the magnetic layer, and a reflecting layer above the second dielectric layer. The magnetic layer is made of a composition modulated material.

Magneto-optic recording medium suited for mark edge recording system and

A method for reproducing information recorded on a magneto-optical recording medium that includes a transparent substrate, a first magnetic layer laminated on the transparent substrate, a second magnetic layer laminated on the first magnetic layer, and a third magnetic layer laminated on the second magnetic layer. The first magnetic layer has an easy axis of magnetization in a plane at room temperature. The second and third magnetic layers have an easy axis of magnetization perpendicular to the substrate. When a laser beam is directed onto the medium a temperature distribution is formed in the laser beam spot. The temperature distribution includes a first area where the direction of magnetization of the first magnetic layer in an in-plane direction, a second area where the magnetization of the third magnetic layer is transferred to the second and the first magnetic layers by exchange bond, and a third area where the temperature of the second magnetic layer is higher than its Curie temperature.

Growing community of inventors

Kawasaki, Japan

Keiji Shono