2004results about How to "Improve coercive force" patented technology

[PROBLEMS] To provide a process for producing a magnetic recording medium, which can simultaneously realize increased high recording density, high impact resistance, and prevention of corrosion, by providing an underlayer which, even when formed at a low gas pressure, can exhibit a high level of coercive force.[MEANS FOR SOLVING PROBLEMS] A process for producing a perpendicular magnetic recording medium, comprising the step of forming a nonmagnetic underlayer (18) having a granular structure, in which crystal particles are grown in a column form, on a substrate, and forming a magnetic recording layer (20) having a granular structure in which magnetic particles are grown in a column form. The process is characterized in that the underlayer (18) is any one of CoCr or CoCrX (wherein X is a nonmagnetic material), CoCr-oxide, and CoCrX-oxide, and the film forming gas pressure of the underlayer (18) is not more than 4 Pa.

A magnetic head for thermally-assisted writing of data to a disk is disclosed. In one illustrative example, the magnetic head includes a write head element and a heating element which is a resistive infared radiator. The heating element is coupled to at least one via pad which is exposed on an outer surface of the magnetic head. This via pad may be the same pad utilized for the write head element or for a read sensor. The heating element is formed beneath or within the pole tip such that it is able to transfer heat to a portion of the disk before the write head element can write data to it Advantageously, the heater facilitates the writing of data to high coercivity media.

A thin-film magnetic head that has a configuration in which the element-formed surface and the opposed-to-medium surface are perpendicular to each other, and a light source is sufficiently distanced from the medium surface is provided. The head comprises at least one near-field-light-generating layer for heating a part of a magnetic medium during write operation by generating a near-field light, having a shape tapered toward a head end surface on the opposed-to-medium surface side, and comprising a near-field-light-generating portion having a light-received surface and a tip reaching the head end surface on the opposed-to-medium surface side, and the light-received surface being sloped in respect to the element-formed surface and being provided in a position where an incident light propagating from a head end surface opposite to the opposed-to-medium surface can reach at least a part of the light-received surface.

In all-optical networks, high speed optical switching and routing becomes one of the most important issues for interconnecting the transport network layers. This invention describes novel polarization-independent high speed optical switches using a digital Faraday rotator, which can also be used for various other optical switching devices. The basic digital Faraday rotator device is composed of (a) a semi-hard or hard iron garnet based magneto-optic crystal having bi-stable magnetization states at zero external magnetic field. (b) a wire winding around the crystal for changing the magnetization states by pulsed current having both fast rise time and short duration. (c) a circuit generating the required current pulses with both polarities. After a driving current pulse excitation to set the magnetization direction, the high coercive force and high remnant squareness in the garnet-based crystal will maintain the saturation magnetization state in the crystal without the need of any external current or magnetic field to sustain the remnant state. The apparatus and the method disclosed in this invention effectively reduces the overall power consumption. By using this digital Faraday rotator device, the polarization independent 1x2 and 2x2 optical switches are designed and fabricated.