Abstract: Recorded information is reproduced based on the displacement of a domain wall using an optical system having a reproducing optical beam with the beam waist diameter thereof satisfying a condition of 2Wo<900 nm. A sharp temperature distribution is formed in the recording medium, and the speed of displacement of the magnetic wall is increased. Even when a disk rotational speed is increased, a reliable domain wall displacement reproduction is thus accomplished.

Abstract: A reproducing laser output can be adjusted to an optinal level. To this end, a magneto-optical disk device 1 comprises a differential amplifier 23 and a shortest recording mark identifier 33 which detect a shortest recording mark reproducing signal corresponding to a component of a shortest recording mark in a reproducing signal obtained by reproducing a magneto-optical disk 100, an envelope detector 33 which detects an amplitude level of the shortest recording mark reproducing signal, a comparator 35 which compares the amplitude level with a reference voltage outputted from the reference voltage source 34, and a drive control section 30 which adjusts the reproducing laser beam to an output level at which the amplitude level is equal to or higher than the reference voltage, based on a comparison result from the comparator 35.

Abstract: The optical beam of the read power corresponding to the rotating velocity is radiated to a recording medium. Thereby, the rotating velocity of optical disc can be detected and the optical beam of read power corresponding to the detected rotating velocity can be radiated to an optical disc.

Abstract: A magneto-optical disk recording and reproducing device, which carries out recording and reproducing for a magnetic super-resolution magneto-optical disk including a recording layer and reproducing layer, has a recording data processing circuit which records long recording marks at different positions between adjacent tracks in a radius direction, each of the long recording marks being larger in diameter than an aperture formed on the reproducing layer by projecting thereon the light beam. According to this arrangement, it is possible to continuously reproduce a data recording area with high accuracy and optimum reproducing power without being affected by adjacent tracks.

Abstract: A reproduction power test method for setting an optimal power of a reproduction light beam for reproducing an information from a domain wall displacement type magneto-optical medium comprises the steps of detecting a domain wall displacement start reproduction power Prdwd at which the domain wall starts to be displaced, and a maximum reproduction power Prmax allowing the domain wall displacement, and determining an optimal reproduction power Pr using a previously obtained relational expression whereby Prdwd, Prmax and the jitter characteristics of a reproduced signal are optimized.

Abstract: The present invention provides a magnetic signal reproducing device including heating means for locally heating a reproducing region of a magnetic recording medium, first reproducing means for reading magnetic information in the reproducing region in a first temperature state to obtain a first reproduced signal, second reproducing means for reading magnetic information in almost the same region as the reproducing region in a second temperature state which is different from the first temperature state to obtain a second reproduced signal, and correcting means for correcting the first reproduced signal based on the second reproduced signal to obtain an information reproducing signal representing information recorded in the reproducing region. According to this, even if a medium temperature in a non-heated region of the magnetic recording medium is shifted from a magnetization compensation point, a signal from the region is prevented from mixing into a reproducing signal.

Abstract: A magnetic domain of a predetermined length is formed on a magneto-optical recording medium with the phase difference altered between the rise of a laser drive signal to generate a pulsed laser beam and the fall of a magnetic head drive signal to generate a magnetic field. A phase difference optimization circuit detects an optimum phase difference corresponding to the lowest error rate from the error rate of a reproduced signal obtained by reproducing the formed magnetic domain. A magnetic head drive signal is newly generated to produce a magnetic field modulated according to a record signal based on the detected optimum phase difference. According to the generated magnetic head drive signal and the first laser drive signal, a magnetic field is applied to the magneto-optical recording medium, and a pulsed laser is directed onto the magneto-optical recording medium to record a signal.

Abstract: The present magnetic recording and reproducing device is provided with a magnetic head (5), which, during recording, applies an external magnetic field to a recording medium (6) having a recording layer made of a ferrimagnetic material, and with a laser light source, which increases the temperature of the recording medium (6) in domains (Tr1 and Tr2) which are opposite the magnetic head (5), but exclude a track to be recorded (Tr), which is a domain for recording. Consequently, a magnetic recording and reproducing device can be provided which is capable of suppressing crosstalk and realizing higher recording density than conventionally.

Abstract: A reproducing apparatus reproduces a signal recorded in a magneto-optical disk. The magneto-optical disk includes a layered structure having a recording layer, an intermediate layer and a reproducing layer. Laser light is illuminated from an optical head to the magneto-optical disk in such an intensity that no magnetic domain is transferred from the recording layer to the reproducing layer only by the laser light. In this state, alternating magnetic field is applied through a magnetic head to the magneto-optical disk, thereby concurrently causing transfer and expansion of a magnetic domain to the reproducing layer. As a result, transfer of the magnetic domain is effected with expansion.

Abstract: A magneto-optic recording medium includes a second auxiliary magnetic film, a first auxiliary magnetic film and a magneto-optic recording film on a substrate. The auxiliary magnetic films change from in-plane magnetization to vertical magnetization at critical temperatures TCR1 and TCR2. Since they have the relation TCR1>TCR2, the magnetic domain transferred from the magneto-optic recording film to the first auxiliary magnetic film at the time of reproduction is expanded in diameter and is transferred to the second auxiliary magnetic film when the temperature profiles of the auxiliary magnetic films inside an optical spot are utilized. The magnetic domain of the magneto-optic recording film can be expanded and transferred, too, by means of magnetostatic coupling by using a non-magnetic film in place of the first auxiliary magnetic film. Pulse reproduction light subjected to power modulation in synchronism with a reproduction clock can be used at the time of reproduction.

Abstract: Recorded information is reproduced based on the displacement of a domain wall using an optical system having a reproducing optical beam with the beam waist diameter thereof satisfying a condition of 2 Wo<900 nm. A sharp temperature distribution is formed in the recording medium, and the speed of displacement of the magnetic wall is increased. Even when a disk rotational speed is increased, a reliable domain wall displacement reproduction is thus accomplished.