102results about How to "Increase in coercivity" patented technology

A perpendicular magnetic recording medium comprising a substrate, a soft underlayer, a seed layer, a non-magnetic FCC NiW alloy underlayer, a non-magnetic HCP underlayer, and a magnetic layer. We have discovered that the combination of a seed layer comprising Ta and a NiW alloy underlayer uniquely improves media recording performance and thermal stability by achieving excellent coercivity of the thin bottom magnetic recording layer and narrow C axis orientation distribution.

In a method for producing an R—Fe—B based rare-earth sintered magnet according to the present invention, first, provided is an R—Fe—B based rare-earth sintered magnet body including, as a main phase, crystal grains of an R₂Fe₁₄B type compound that includes a light rare-earth element RL, which is at least one of Nd and Pr, as a major rare-earth element R. Thereafter, the sintered magnet body is heated while a heavy rare-earth element RH, which is at least one element selected from the group consisting of Dy, Ho and Tb, is supplied to the surface of the sintered magnet body, thereby diffusing the heavy rare-earth element RH into the rare-earth sintered magnet body.

A magnetic recording device including a longitudinal magnetic recording medium. The longitudinal magnetic recording medium includes a magnetically soft underlayer disposed under a longitudinal recording layer. A perpendicular write head is utilized to write data to the longitudinal magnetic recording medium wherein the longitudinal recording layer is disposed within an effective write gap formed by the perpendicular write head and the underlayer. The longitudinal component of the perpendicular write head is sufficient to switch the magnetic grains in the recording layer in the presence of the perpendicular field. The magnetic recording medium can have a high areal density and improved magnetic properties.

A method and structure for a non-volatile magnetic random access memory (MRAM) device that has a stable magnetic electrode, an oxide layer adjacent the stable magnetic electrode, and a free magnetic electrode. The oxide layer is between the stable magnetic electrode and the free magnetic electrode. In the invention, a conductor is connected to a stable magnetic electrode. The oxide layer has a resistance at levels to allow sufficient power dissipation to lower the anisotropy of the free magnetic electrode through current induced heating. Current-induced heating is used in combination with spin-transfer torque or a magnetic field to switch the free magnetic electrode.

A magnetic recording medium, the order of layers in which is the substrate, the soft underlayer, the seedlayer, the 1^st RuCr_x-containing interlayer, the 2^nd RuCr_x-containing interlayer and the magnetic recording layer with preferably a oxides or nitrides-containing magnetic layer comprising grains, is disclosed. High-chromium ruthenium-chromium alloy used as inter layers significantly enhances coercivity and SMNR preferably due to the improved lattice match between RuCr inter layers and CoPt-based magnetic recording layers, and the surface energy of RuCr layers contributes to the performance improvement with the high-chromium addition into Ru inter layers.

A current perpendicular to plane (CPP) GMR sensor having first and second outer pinned layers and a trilayer free layer therebetween. The free layer includes first and second outer magnetic layers, and a partially oxidized magnetic layer disposed there between. The middle partially oxidized layer is antiparallel coupled with the outer magnetic layers of the free layer by first and second coupling alyers which prevent oxygen migration from the central layer into the outer magnetic layers of the free layer. The partial oxidation of the middle layer provides a limited amount of electrical resistance at a desired location within the free layer to increase GMR.

A permanent magnet motor includes: a rotor and a stator; and a plurality of permanent magnets placed on either the rotor or the stator. Each permanent magnet is an R—Fe—B based rare-earth sintered magnet including a light rare-earth element RL (at least one of Nd and Pr) as a major rare-earth element R, and partially includes a high coercivity portion in which a heavy rare-earth element RH (at least one element selected from the group consisting of Dy, Ho and Tb) is diffused in a relatively higher concentration than in the other portion.

Permanent magnets in which the ferromagnetic phase is matched with the grain boundary phase, and permanent magnets in which magnetocrystalline anisotropy in the vicinity of the outermost shell of the major phase is equivalent in intensity to that in the inside to suppress nucleation of the inverse magnetic domain. Guideline for designing permanent magnets having high magnetic performance is provided.

A magnetic recording medium according to one aspect of the present invention includes a substrate; an underlayer positioned on the substrate and made of a material having a body-centered-cubic crystalline structure or a B2 crystalline structure; a first intermediate layer positioned on the underlayer and having a hexagonal closest packing crystalline structure, and being made of Co or a Co alloy; a second intermediate layer positioned on the first intermediate layer and having a hexagonal closest packing crystalline structure, and being made of a material selected from the group consisting of Ru, Ti, Re, Zr, Hf, and a Ru alloy; and a magnetic layer positioned on the second intermediate layer and including multiple magnetic grains each having a hexagonal closest packing crystalline structure and an axis of easy magnetization oriented in a direction substantially parallel to a surface of the substrate, wherein the magnetic grains are isolated from each other.

An R—Fe—B based rare-earth sintered magnet according to the present invention includes, as a main phase, crystal grains of an R₂Fe₁₄B type compound that includes Nd, which is a light rare-earth element, as a major rare-earth element R. The magnet includes a heavy rare-earth element RH (which is at least one of Dy and Tb) that has been introduced through the surface of the sintered magnet by diffusion. The magnet has a region in which the concentration of the heavy rare-earth element RH in a grain boundary R-rich phase is lower than at the surface of the crystal grains of the R₂Fe₁₄B type compound but higher than at the core of the crystal grains of the R₂Fe₁₄B type compound.

An R—Fe—B based anisotropic sintered magnet according to the present invention has, as a main phase, an R₂Fe₁₄B type compound that includes a light rare-earth element RL (which is at least one of Nd and Pr) as a major rare-earth element R, and also has a heavy rare-earth element RH (which is at least one element selected from the group consisting of Dy and Tb). In the crystal lattice of the main phase, the c-axis is oriented in a predetermined direction. The magnet includes a portion in which at least two peaks of diffraction are observed within a 2θ range of 60.5 degrees to 61.5 degrees when an X-ray diffraction measurement is carried out using a CuK α ray on a plane that is located at a depth of 500 μm or less under a pole face of the magnet and that is parallel to the pole face.

A permanent magnet has a grain structure that includes a main phase and a grain boundary phase that is primarily composed of a first metal. A second metal that enhances the coercivity of the permanent magnet and a third metal that has a lower standard free energy of oxide formation than the first metal and the second metal are diffused in the permanent magnet, and the third metal is present in the form of an oxide in the grain boundary phase.

A method for producing RFeB system sintered magnet composed of at least two unit sintered magnets bonded to each other at flat bonding surfaces, each unit sintered magnet composed of crystal grains whose main phase is made of R₂Fe₁₄B containing, as a main rare-earth element R, light rare-earth element R_L wherein at least one element selected from the group of Nd and Pr. Paste prepared by mixing organic matter and metallic powder containing at least one element selected from heavy rare-earth elements R_H of Dy, Ho and Tb is sandwiched between neighboring unit sintered magnets, and a grain boundary diffusion treatment is performed. Coercivity is improved by this grain boundary diffusion treatment. Since an oxide or similar compound of R_H and/or R_L is formed at boundary of unit sintered magnets, the influence of eddy current during a period of use is suppressed, and unit sintered magnets are strongly bonded together.

A method of manufacturing an R-T-B rare earth sintered magnet includes a process of disposing and sintering a compact of a first alloy powder and an alloy material of a second alloy in a chamber of a sintering furnace. The first alloy consists of R which represents a rare earth element, T which represents a transition metal essentially containing Fe, a metal element M which represents Al and/or Ga, B, Cu, and inevitable impurities. The first alloy contains 11 at % to 17 at % of R, 4.5 at % to 6 at % of B, 0 at % to 1.6 at % of M, and T as the balance, and Dy content in all of the rare earth elements is 0 at % to 29 at %. The second alloy consists of R which represents a rare earth element, T which represents a transition metal essentially containing Fe, a metal element M which represents Al and/or Ga, B, Cu, and inevitable impurities. The second alloy contains 11 at % to 20 at % of R, 4.5 at % to 6 at % of B, and 0 at % to 1.6 at % of M, and T as the balance, and Dy content in all of the rare earth elements is 0 at % to 29 at %.