570results about "Protective coatings for layers" patented technology

An MTJ in an MRAM array or in a TMR read head is comprised of a capping layer with a lower inter-diffusion barrier layer, an intermediate oxygen gettering layer, and an upper metal layer that contacts a top conductor. The composite capping layer is especially useful with a moderate spin polarization free layer such as a NiFe layer with a Fe content of about 17.5 to 20 atomic %. The capping layer preferably has a Ru / Ta / Ru configuration in which the lower Ru layer is about 10 to 30 Angstroms thick and the Ta layer is about 30 Angstroms thick. As a result, a high dR / R of about 40% is achieved with low magnetostriction less than about 1.0 E−6 in an MTJ in an MRAM array. Best results are obtained with an AlOx tunnel barrier layer formed by an in-situ ROX process on an 8 to 10 Angstrom thick Al layer.

A method of forming a discrete track recording pattern in a magnetic recording disk. In one embodiment, the discrete track recording pattern may be formed in a NiP layer continuous throughout the discrete track recording pattern. Alternatively, the discrete track recording pattern may be formed in a substrate.

In a method of evaluating surface tension of a solid body surface, selection is made of at least three liquid samples having different surface tensions, and contact angles between the respective liquid samples and the solid body surface are measured. Thereby, a correlation between cosines (Y) of the contact angles and surface tensions (X) of the liquid samples is derived as a logarithmic function. Surface tension of the solid body surface is evaluated by the use of a value of X that is calculated by substituting 1 for Y in the correlation. When evaluated by the foregoing evaluation method, a magnetic disk has a surface where the value of X, when 1 is substituted for Y, is greater than 0 and no greater than 17 mN / m.

Disclosed is a method of manufacturing magnetic disks, comprising a magnetic layer, a protective layer, and a lubricating layer on a substrate. In the process, a lubricant alpha comprising a compound denoted by chemical formulaHO—CH2—CH(OH)—CH2—O—CH2—CF2(—O—C2F4)p-(O—CF2)q-O—CF2—CH2—O—CH2—CH(OH)—CH2—OHwherein p and q are natural number,and a compound denoted by chemical formulaHO—CH2—CF2(—O—C2F4)m-(O—CF2)n-O—CF2—CH2—OHwherein m and n are natural number,is fractionated by molecular weight to prepare a lubricant a having a weight average molecular weight (Mw) of from 3,000 to 7,000 and a molecular weight dispersion of less than or equal to 1.2;a lubricant beta comprising a compound denoted by the chemical formulaHO—CH2—CF2(—O—C2F4)m-(O—CF2)n-O—CF2—CH2—OHwherein m and n are natural number,is fractionated by molecular weight to prepare a lubricant b having a weight average molecular weight (Mw) of from 2,000 to 5,000 and a molecular weight dispersion of less than or equal to 1.2;a lubricant c comprising a mixture of lubricants a and b is prepared; anda film of lubricant c is formed on a protective layer provided on a substrate to form a lubricating layer. A magnetic disk comprising a magnetic layer, a protective layer, and a lubricating layer on a substrate, in which the lubricating layer has been formed on the protective layer is also enclosed.

In a magnetic disk having a magnetic layer, a protection layer, and a lubrication layer formed on a substrate in this order, a surface free energy γS of a surface of the magnetic disk derived by an extended Fowkes equation is greater than 0 and no greater than 24 mN / m. γSd (dispersion force component of surface free energy) forming the surface free energy γS is greater than 0 and no greater than 17 mN / m, γSp (dipole component of surface free energy) forming the surface free energy γS is greater than 0 and no greater than 1 mN / m, and γSh (hydrogen bonding force component of surface free energy) forming the surface free energy γS is greater than 0 and no greater than 6 mN / m.

A perpendicular magnetic recording medium, including a suitable lubricating layer with sufficient durability, moisture resistance, and contamination resistance and also maintaining an R / W characteristic. The perpendicular magnetic recording medium 100 includes a magnetic recording layer 122, a medium protective layer 126, and a lubricating layer 128 in this order on a base 110. The medium is made using a CF bond density measuring step of measuring a CF bond density of a lubricant; and a lubricating layer forming step of forming a lubricating layer with the lubricant when the measured CF bond density is 2.0×1022 to 2.7×1022 atoms / cm3.

A magnetic recording disk has a high-adhesion lubricant layer that permits an operation at an extremely low level of flying height of 12 nm or less without troubles and which is capable of preventing the migration at a high-speed rotation, and comprises a substrate, a magnetic layer formed on the substrate, a protective layer formed on the magnetic layer and a lubricant layer formed on the protective layer, the lubricant layer containing a compound (A) of the general formula (I), wherein each of p and q is an integer of 1 or more, anda compound (B) having a perfluoropolyether main chain having two end moieties each of which contains a carbon atom or an oxygen atom to which a hydroxyl-containing hydrocarbon group that optionally contains ether bond(s) is bonded, and a process for the manufacture thereof is provided.

A vertical magnetic recording disc (100) includes a base (10), a magnetic recording layer (22), and a medium protection layer (26). The magnetic recording layer (22) is a ferromagnetic layer having a granular structure where a granular portion is formed. The medium protection layer (26) contains nitrogen (N) atoms and carbon (C) atoms with a number ratio (N / C) in a range from 0.050 to 0.150. In a Raman spectrum obtained by exciting the medium protection layer (26) by argon ion laser light of wavelength 514.5 nm, from which a fluorescence is removed, the peak ratio Dh / Gh is in a range from 0.70 to 0.95, when a D peak Dh appearing in the vicinity of 1350 cm−1 is separated from G peak Gh appearing in the vicinity of 1520 cm−1 by the Gauss function.

A magnetic disk comprises a magnetic layer and a protective layer sequentially formed on a disk-shaped substrate and has a principal surface to which data is recorded, and a side surface portion both of which are coated with the protective layer. The protective layer on the side surface portion is thinner than the protective layer on the principal surface. Preferably, the side surface portion includes a side wall surface, and a chamfered surface lying between the side wall surface and the principal surface, and at least the protective layer on the chamfered surface is thinner than the protective layer on the principal surface.