Hitachi Maxell, Limited

Trek, Inc.

Nec Corporation

Nih N University

Katsuji Nakagawa

Norio Ohta

Katsusuke Shimazaki

Hiroyuki Awano

Hiroki Takao

Manabu Tani

Akiyoshi Itoh

Akiyoshi Itou

Bruce T Williams

Toshio Uehara

Akiyoshi Ito

Kazuko Inoue

Masafumi Yoshihiro

Masaki Itoh

Mitsuru Sakai

Masaki Sekine

Akio Morimoto

A magneto-optical recording medium and a method for recording and reproduction thereon are provided in order to reproduce information recorded by multi-valued recording at a high S/N ratio. Disclosed is a magneto-optical recording medium including two magnetic layers capable of four-valued recording based on four combined magnetization states. Magnitudes of reproduction signals concerning the four magnetization states, obtained upon reproduction at a wavelength &#x3bb;, are different from those obtained upon reproduction at a wavelength &#x3bb;. The two magnetic layers, on which a signal (a) is recorded, are irradiated with light beams having the wavelengths &#x3bb;and &#x3bb;respectively. Signals (d), (e) reproduced from respective reflected light beams are sliced by using at least one slice level to obtain two-valued or higher multi-valued reproduction signals respectively. The two-valued or higher multi-valued reproduction signals (f), (g) from the respective wavelengths are mutually subjected to logical operation to reproduce recorded information (i).

Method for recording and reproduction on a magneto-optical recording medium

A magneto-optical recording medium has magneto-optical recording layers () and reproducing layers (). The information recorded in the reproducing layers are reproduced by means of reproducing light beams () of different wavelengths, respectively. In reproduction, magnetic domains () recorded in the recording layers are transferred in the reproducing layers formed on the respective recording layers, the transferred magnetic domains () are enlarged with an external magnetic field, and the information is reproduced. Since information is recorded and reproduced for each recording layer, the recording density is improved. Further since the reproduction signals are amplified by the magnetic domain enlargement, the C/N is improved.

Magneto-optical reproducing method using a plurality of different reproducing beams

A magnetic element having an improved MR rate. The magnetic element is made up of plural layered films of different compositions and exhibits a magneto-resistance effect that the magneto-resistance value is changed on application of a magnetic field. The magnetic element includes a recess for transmitting the current along the layering direction of the layered films. The current flows through the portion of the magnetic element not having the recess so as to have a component along the film layering direction A, with the result that electrons taking part in current conduction may be propagated as the electrons traverse the boundary surfaces of the plural layered films.

Magnetic device, magnetic head and magnetic adjustment method

A magneto-optical recording medium has magneto-optical recording layers ( ) and reproducing layers ( ). The information recorded in the reproducing layers are reproduced by means of reproducing light beams ( ) of different wavelengths, respectively. In reproduction, magnetic domains ( ) recorded in the recording layers are transferred in the reproducing layers formed on the respective recording layers, the transferred magnetic domains ( ) are enlarged with an external magnetic field, and the information is reproduced. Since information is recorded and reproduced for each recording layer, the recording density is improved. Further since the reproduction signals are amplified by the magnetic domain enlargement, the C/N is improved.

Magneto-optical reproducing method using a plural of different reproducing beams

An electrostatic force microscope wherein electrostatic force applied to the detector is determined through obtaining the field distribution on several different shaped detectors with the calculation of the voltage distribution near the detector with the Finite Element Method to direct the measurement of the absolute charge amount on surface under test so that one can define the differences between the analysis and the results from the parallel plate model. Of interest is how large the error in the charge detection occurs in conjunction with thickness change of dielectric materials to be tested. There is provided a detector with cantilever which has proper shape for the spatial resolution of 10&mgr; made out of nickel foil for an electrostatic force microscope and the electrostatic force which appeared on it has been calculated.

Electrostatic force detector with cantilever for an electrostatic force microscope

The magneto-optical recording medium has a magnetic domain magnification reproducing layer and an information recording layer. Clock marks are formed on the information recording layer, making it possible to generate a reproducing clock on the basis of these. The clock marks are detected either by irradiating directly with light of wavelength &lgr; (&lgr; &ne;&lgr; ), being different from the light of wavelength &lgr; which is used for reproducing the recording marks, or by applying a direct-current magnetic field, transferring and enlarging the clock marks on to the magnetic domain magnification reproducing layer, and detecting the reproduction signals from this magnetic domain magnification reproducing layer. Since the reproducing clock is in exact synchronisation with the recording marks, it is eminently suitable as a clock for pulse-modulated reproducing light and reproducing magnetic fields used when reproducing the reproducing layer.

Magneto-optical recording medium having clock-marks on recording layer and apparatus for recording and reproducing same

An electrostatic force microscope for measuring electrostatic force of a sample under test including a detector comprising a cantilever arm having a tip formation at one end and located so that electrostatic force is induced at the tip due to electrostatic charge on the sample under test, an optical system for transforming bending of the cantilever arm due to electrostatic force induced at the tip into an electrical signal containing a frequency component of the electrostatic force induced at the detector tip, a source for applying bias voltage to the detector, a detector for detecting the frequency component of the electrostatic force induced at the detector tip so that a measurement of electrostatic force on the sample under test can be obtained, and an electrostatic shield operatively associated with the cantilever arm. The shield is located between the cantilever arm and the sample under test, in particular in close spaced relation to the arm. The cantilever arm and the shield are maintained at the same electrical potential so that lines of electrostatic force are terminated at the shield.

Electrostatic force detector with cantilever and shield for an electrostatic force microscope

Magneto-optical recording medium and method for recording and

An optical information recording medium according to the present invention is featured by its recording layer which contains a compound of tellurium (Te), selenium (Se) and nitrogen (N). The thickness of the recording layer 2 favorably ranges from about 100 angstroms (.ANG.) to about 1000 .ANG. and more favorably from 180 .ANG. to 400 .ANG.. The content of Se in the recording layer 2 favorably lies within a range from 2 to 40 atomic percent, more favorably from 10 to 30 atomic percent. The content of N is favorably to be from 2 to 20 atomic percent, and more favorably from 2 to 10 atomic percent.

Growing community of inventors

Tokyo, Japan

Katsuji Nakagawa