Abstract: A nitride-contained semiconductor laser element includes a layer formed of an Alx1Ga1−x1N (0.08≦x1≦0.2) lower clad layer, an active layer formed of an alternate multilayer structure including an InwGa1−wN well layer and an InvGa1−vN barrier layer, and an Alx2Ga1−x2N (0.08≦x2≦0.2) upper clad layer layered in this order on a substrate, one or a plurality of InzGa1−zN (0≦z≦0.2) buffer layer(s) of 200 nm or less in thickness being disposed in the lower clad layer and/or the upper clad layer.

Abstract: A nitride-type compound semiconductor laser device includes a substrate and a layered structure provided on the substrate. A light absorption layer having a bandgap smaller than a bandgap of an active layer in the layered structure is provided in a position between the cladding layer, which is provided on a side opposite to a mount surface with respect to the active layer, and a surface of the layered structure which is opposite to the mount surface.

Abstract: A driver circuit substrate is prepared and a mirror substrate is so provided as to be placed on the driver circuit substrate. Nine mirror elements are lad out on the mirror substrate in a 3×3 matrix form. The mirror elements are prepared by a microelectromechanical system (MEMS). An insulating substrate is provided on the driver circuit substrate and a driver circuit which drives a light reflecting mirror element is provided on the insulating substrate. The driver circuit substrate is connected to the mirror substrate via a resin layer of a thermosetting adhesive or the like.

Abstract: In a method for making molten metal, reduced metal which is produced in a direct reduction furnace is melted in a melting furnace located in the close vicinity of the direct reduction furnace to produce the molten metal. The method includes the steps of putting the reduced metal into a metallic container, and loading the container containing the reduced metal into the melting furnace. The method may further includes, before the step of loading the container containing the reduced metal into the melting furnace, a step of cooling the surface of the container so that the surface temperature of the container is 500° C. or less.

Abstract: A gallium nitride type semiconductor laser device includes: a substrate; and a layered structure formed on the substrate. The layered structure at least includes an active layer of a nitride type semiconductor material which is interposed between a pair of nitride type semiconductor layers each functioning as a cladding layer or a guide layer. A current is injected into a stripe region in the layered structure having a width smaller than a width of the active layer. The width of the stripe region is in a range between about 0.2 &mgr;m and about 1.8 &mgr;m.

Abstract: A gallium nitride type semiconductor laser device includes: a substrate; and a layered structure formed on the substrate. The layered structure at least includes an active layer of a nitride type semiconductor material which is interposed between a pair of nitride type semiconductor layers each functioning as a cladding layer or a guide layer. A current is injected into a stripe region in the layered structure having a width smaller than a width of the active layer. The width of the stripe region is in a range between about 0.2 &mgr;m and about 1.8 &mgr;m.

Abstract: A gallium nitride semiconductor laser device has an active layer (6) made of a nitride semiconductor containing at least indium and gallium between an n-type cladding layer (5) and a p-type cladding layer (9). The active layer (6) is composed of two quantum well layers (14) and a barrier layer (15) interposed between the quantum well layers, and constitutes an oscillating section of the semiconductor laser device. The quantum well layers (14) and the barrier layer (15) have thicknesses of, preferably, 10 nm or less. In this semiconductor laser device, electrons and holes can be uniformly distributed in the two quantum well layers (14). In addition, electrons and holes are effectively injected into the quantum well layers from which electrons and holes have already been disappeared by recombination. Consequently, the semiconductor laser device has an excellent laser oscillation characteristic.

Abstract: A nitride semiconductor laser device having a low threshold current and low noise is provided. The laser device includes n-type and p-type layers made of nitride semiconductor and formed on a substrate, and a light emitting layer between the n-type and p-type layers. The light emitting layer is formed of a well layer or a combination of well and barrier layers. At least the well layer is made of nitride semiconductor containing element X, N and Ga, wherein element is at least one selected from the group consisting of As, P and Sb. The atomic fraction of element X is smaller than that of N. A maximum width through which current is injected into the light emitting layer via the p-type layer is from 1.0 &mgr;m to 4.0 &mgr;m.

Abstract: A gallium nitride semiconductor laser device has an active layer (6) made of a nitride semiconductor containing at least indium and gallium between an n-type cladding layer (5) and a p-type cladding layer (9). The active layer (6) is composed of two quantum well layers (14) and a barrier layer (15) interposed between the quantum well layers, and constitutes an oscillating section of the semiconductor laser device. The quantum well layers (14) and the barrier layer (15) have thicknesses of, preferably, 10 nm or less. In this semiconductor laser device, electrons and holes can be uniformly distributed in the two quantum well layers (14). In addition, electrons and holes are effectively injected into the quantum well layers from which electrons and holes have already been disappeared by recombination. Consequently, the semiconductor laser device has an excellent laser oscillation characteristic.

Abstract: The gallium nitride group semiconductor laser device of this invention includes an active layer made of a nitride semiconductor formed between cladding layers and/or guide layers made of a nitride semiconductor on a substrate, wherein a light absorption layer is formed between the substrate and one of the cladding layers located closer to the substrate, the light absorption layer being made of a semiconductor having an energy gap substantially equal to or smaller than an energy gap of the active layer.

Abstract: To provide an MR composite head wherein damage of an MR element due to discharge of the static electricity is surely prevented with a simple configuration without degrading reproduction performance of the MR composite head, a first and a second magnetic shield layer (14 and 17), whereby the MR layer (20) is sandwiched, are designed to be grounded through a suspension (25). In an embodiment, a conductive member (24) is formed at an upper surface (11b) of the MR composite head (11) opposite to a facing surface (11a) facing to a magnetic disk (31), for electrically connecting the first and the second magnetic shield layer (14 and 17) to a slider (12) which is electrically connected to the suspension (25).

Abstract: A performance evaluation method of an MR head whereby resolution performance of an MR head can be estimated, an isolated repreoduction wave form V(t) of the MR head is approximated by an equation V(t)=1/(1+(2t/PW50).sup.P), t denoting time difference from a timing which gives a peak value of the isolated reproduction wave form V(t), and PW50 denoting a half-peak-width where the isolated reproduction wave form V(t) shows more than 50% of the peak value. The resolution performance of the MR head is evaluated according to the order value P of the above equation which gives the most likelihood approximation of the isolated wave form, together with the half-peak-width PW50 relative to a minimum bit-interval to be reproduced by the MR head.

Abstract: For evaluating Barkhausen noise of a magnetoresistive head in a frequency range where it is used for read/write of recording media, in an inspection device of a magnetoresistive head (10) of the invention having an external magnetic field generator (1) for applying an external magnetic field to a magnetoresistive element (11) of the magnetoresistive head, and a noise measurement section (2) for evaluating noise of a signal output of the magnetoresistive element according to the external magnetic field, an inductive head (20) is applied in the external magnetic field generator for generating the external magnetic field.

Abstract: The dielectric multilayered reflector of the invention is formed on at least one of two emitting surfaces of a semiconductor laser device. The dielectric multilayered reflector includes: a multilayered structure formed by stacking a plurality of layers; and a layer made of magnesium difluoride. In this dielectric multilayered reflector, the multilayered structure includes at least one layer made of an oxide dielectric material and the layer made of magnesium difluoride is formed on a surface of an outermost layer of the multilayered structure.

Abstract: A semiconductor laser device includes: a lower cladding layer; an upper cladding layer having a bottom and a strip-shaped ridge portion projecting from the bottom; a II-VI compound semiconductor active layer interposed between the lower cladding layer and the upper cladding layer; and a burying blocking layer made of an aromatic polyamide resin formed on a bottom of the upper cladding layer so as to be in contact with sides of the stripe-shaped ridge portion.

Abstract: A semiconductor laser device includes a substrate and a laminated structure formed on a top face of the substrate. The laminated structure includes (a) first and second guide layers and (b) a quantum well structure of compound semiconductor interposed between the first and second guide layers. The quantum well structure serves as a resonator of the device and includes at least one quantum well layer and at least one barrier layer. The quantum well layer has a thickness L.sub.z and the barrier layer has the energy gap larger than the energy gap of the quantum well layer so as to form a energy difference V.sub.0 between the bottom of the conduction band of the quantum well layer and the bottom of the conduction band of the barrier layer. The relationship represented by formula (I) is satisfied:L.sub.z .ltoreq.h / 2 (2m*V.sub.0).sup.1/2 (I)wherein h is Planck's constant and m* is the effective mass of electrons within the quantum well layer.

Abstract: A semiconductor laser device includes a substrate and a laminated structure formed on a top face of the substrate. The laminated structure includes (a) first and second guide layers and (b) a quantum well structure of compound semiconductor interposed between the first and second guide layers. The quantum well structure serves as a resonator of the device and includes at least one quantum well layer and at least one barrier layer. The quantum well layer has a thickness L.sub.z and the barrier layer has the energy gap larger than the energy gap of the quantum well layer so as to form a energy difference V.sub.O between the bottom of the conduction band of the quantum well layer and the bottom of the conduction band of the barrier layer. The relationship represented by formula (I) is satisfied:L.sub.z .ltoreq.h / 2 (2m.sup.* V.sub.O).sup.1/2 (I)wherein h is Planck's constant and m.sup.* is the effective mass of electrons within the quantum well layer.

Abstract: A method for erasing information recorded on a magnetic tape by a magnetic erase head having a magnetic core having a magnetic gap of a predetermined width and a coil wound on the core. An erasing current is flown through the coil to generate an erasing magnetic field above the magnetic gap. The magnetic field generated by that current has a profile defined by a first zero point, first and second peak points, and a second zero point above the magnetic erase head. The magnetic tape having information recorded therein through the magnetic field is moved above the magnetic erase head. The frequency of the erasing current and a moving speed of the magnetic tape relative to the magnetic erase head are set such that the magnetic field changes in phase at least three times during a time in which the magnetic tape is moved in a moving direction of the magnetic tape by a distance which is determined by the first zero point and the first peak point of the magnetic field profile.

Abstract: In order to improve a wear resistance and recording and reproducing properties of a magnetic head which has a magnetic core having a magnetic gap and a penetrated hole, a pair of reinforcing members holding the magnetic core therebetween, each having an opening corresponding to the penetrated hole, and a winding wound onto the magnetic core and the reinforcing members through the penetrated hole and the opening, each of the reinforcing member is a non-magnetic substrate which is made of a ceramic material essentially consisting of 2-30 weight % CaO, 2-50 weight % TiO.sub.2, and 30-80 weight % NiO and having an average grain size of 2 .mu.m or less. Alternatively, another ceramic is used which essentially consists of 2-30 weight % CaO, 2-50 weight % TiO.sub.2, 30-80 weight % NiO, and 0.2-1 weight % Al.sub.2 O.sub.3, and having an average grain size of 2 .mu.m or less, excluding zero.

Abstract: A semiconductor laser device includes a substrate and a laminated structure formed on a top face of the substrate. The laminated structure includes (a) first and second guide layers and (b) a quantum well structure of compound semiconductor interposed between the first and second guide layers. The quantum well structure serves as a resonator of the device and includes at least one quantum well layer and at least one barrier layer. The quantum well layer has a thickness L.sub.z and the barrier layer has the energy gap larger than the energy gap of the quantum well layer so as to form a energy difference V.sub.0 between the bottom of the conduction band of the quantum well layer and the bottom of the conduction band of the barrier layer. The relationship represented by formula (I) is satisfied:L.sub.z <h/2(2m*V.sub.0).sup.1/2 (I)wherein h is Planck's constant and m* is the effective mass of electrons within the quantum well layer.