268 results about "Hexagonal ferrite" patented technology

The magnetic tape includes a magnetic layer having ferromagnetic powder and a binder on a non-magnetic support, in which the magnetic layer includes a timing-based servo pattern, the ferromagnetic powder is ferromagnetic hexagonal ferrite powder having an activation volume equal to or smaller than 1,600 nm3, and an edge shape of the timing-based servo pattern specified by a magnetic force microscope observation is a shape in which a difference (l99.9−l0.1) between a value l99.9 of a cumulative frequency function of 99.9% of a position deviation width from an ideal shape in a longitudinal direction of the magnetic tape and a value l0.1 of the cumulative frequency function of 0.1% thereof is equal to or smaller than 180 nm.

The magnetic tape includes a magnetic layer containing ferromagnetic hexagonal ferrite powder, abrasive, and binder on a nonmagnetic support, wherein the ferromagnetic hexagonal ferrite powder exhibits an activation volume of less than or equal to 1,800 nm3, and inclination, cos θ, of the ferromagnetic hexagonal ferrite powder relative to a surface of the magnetic layer as determined by sectional observation by a scanning electron transmission microscope is greater than or equal to 0.85 but less than or equal to 1.00.

An aspect of the present invention relates to a magnetic tape comprising a magnetic layer containing a ferromagnetic powder and a binder on a nonmagnetic support, whereinthe ferromagnetic powder is a hexagonal ferrite powder,squareness in a vertical direction without demagnetizing field correction of the magnetic layer ranges from 0.6 to 1.0, andthe magnetic layer further comprises a compound in which a substituent selected from the group consisting of a carboxyl group and a hydroxyl group is directly substituted into a ring structure comprising a double bond and having a ClogP falling within a range of 2.3 to 5.5.

To provide a magnetic recording medium which undergoes little effect of thermal fluctuation and provides a high short wavelength output and C / N ratio when reproduction is conducted using MR head, the magnetic recording medium includes a non-magnetic layer having a non-magnetic powder dispersed in a binder provided on a support and a magnetic layer having a ferromagnetic powder dispersed in a binder provided on the non-magnetic layer, wherein the ferromagnetic powder comprises a hexagonal ferrite magnetic powder having an average diameter of from 10 to 35 nm and a coercive force of from 135 to 400 kA / m; the magnetic layer has a coercive force of from 135 to 440 kA / m; and a product of an anisotropic magnetic field of the magnetic layer and an average particle volume of the hexagonal ferrite magnetic powder is from 1.2×106 to 2.4×106 kA / m·nm3.

An aspect of the present invention relates to a magnetic recording medium, which comprises a magnetic layer comprising ferromagnetic powder and binder on a nonmagnetic support, wherein the ferromagnetic powder is ferromagnetic hexagonal ferrite powder comprising 3 to 12 weight percent of Al, based on Al2O3 conversion, relative to 100 weight percent of a total weight of the powder, the magnetic layer further comprises abrasive, and a maximum plan view surface area of the abrasive as determined for a 4.3 μm×6.3 μm rectangular region of the magnetic layer by a scanning electron microscope is less than 0.06 percent relative to 100 percent of a total surface area of the region.

An aspect of the present invention relates to a magnetic particle obtained by heat-treating a hexagonal ferrite magnetic material in reducing atmosphere containing hydrocarbon gas.

Provided is a magnetic recording medium exhibiting good electromagnetic characteristics in high-density recording The magnetic recording medium employed for magnetically recording signals with a track width equal to or less than 2.0 μm and reproducing the magnetically recorded signals, wherein said magnetic recording medium comprises a magnetic layer comprising a hexagonal ferrite ferromagnetic powder and a binder or comprises a nonmagnetic layer comprise a nonmagnetic powder and a binder and a magnetic layer comprising a hexagonal ferrite ferromagnetic powder and a binder in this order on a nonmagnetic support. Said magnetic layer has a thickness equal to or less than 0.2 μm, and said hexagonal ferrite ferromagnetic powder has an average plate diameter being 1 / 30 or less of the magnetically recorded track width as well as ½ or less of the thickness of the magnetic layer.