2results about "Coating by liquid dispersion" patented technology

The present invention provides hexagonal ferrite magnetic powder which is extremely useful in achieving both an increase in recording density and an increase in SNR of a magnetic recording medium, is crystalline and has a high saturation magnetization. The hexagonal ferrite magnetic powder contains Bi in a range of a Bi / Fe molar ratio of 0.035 or less, has a saturation magnetization σs of 42.0 Am 2 / kg or more, and a Dx volume of 1800 nm 3 or less, based on a microcrystal diameter. The magnetic powder can be produced by a method for producing hexagonal ferrite magnetic powder, comprising a process of immersing hexagonal ferrite magnetic powder containing Bi in a solution in which a compound X that forms a complex with Bi is dissolved, thereby performing a treatment of dissolving a part of the Bi present in the hexagonal ferrite magnetic powder into the solution.

The purpose of the present invention is to provide a magnetic recording medium that has excellent running stability even when stored in a high-temperature environment.　The present invention provides a magnetic recording medium in which, when dynamic viscoelasticity measurement is performed on the magnetic recording medium at a frequency of 10 Hz and a heating rate of 2°C / min, the average value A(E") of the loss elastic modulus E" in the temperature range of 60°C to 65°C is 0.06 GPa or less, and the average height Rpk of the protruding peaks measured using a non-contact profilometer using optical interference is 2.4 nm or less.