The recording form of the magnetic recording material is divided into three types: 1. longitudinal magnetic recording material, and the magnetization direction of the signal recorded on the surface of the magnetic layer coincides with the moving direction of the recording material, such as an audio tape. 2.transverse magnetic recording material, the direction of signal magnetization recorded on the surface of the magnetic layer is perpendicular to or close to the direction of movement of the recording material, such as a video tape. 3 perpendicular magnetic recording material, the direction of signal magnetization recorded on the surface of the magnetic layer is perpendicular to the surface of the recording material, such as a magneto-optical disk.
Since the development of magnetic recording materials, the recording wavelength has been shortened from the initial 1000 μm to less than 1 μm, and the Hc has been increased from 102 Oe to more than 103 Oe. The most widely used materials are oxide magnetic powder (mainly are Γ-Fe2O3, CrO2 and cobalt-coated magnetic powder) and alloy magnetic powder.
In the past 20 years, the material performance has been improved from the following three ways to meet the requirements of high-density recording:
1. Seeking to improve magnetic anisotropy, such as ultra-fine particle, high-axis ratio needle-shaped magnetic powder, CrO2 and cobalt-coated magnetic powder and Hc>1000Oe New materials such as alloy magnetic powder.
2. Thinning the magnetic layer and achieving high density recording by improving the coating technology. It is common to use both oxygen removal and adhesive removal. The former is replaced by metal powder, and the latter is made into a thin film. The alloy film is the result of the combination of the two methods.
3. Making fundamental improvements from the recording principle and recording mode. At present, when the density is increased in the general longitudinal recording, the generated demagnetizing field can reduce the signal and generate a vertical component. This method can be overcomed by increasing the Hc and thinning the magnetic layer, but there are certain limits.
Therefore, a perpendicular recording material appears, and the demagnetizing field generated by it tends to zero as the density increases, and vertical recording does not require high Hc and very thin materials, it effectively overcomes the achilles heel of longitudinal recording at high density recording. Vertical recording requires that the material have uniaxial anisotropy on the surface of the perpendicular magnetic layer.
The picture below are two micrographs of our FeCoTaZr alloy sputtering target, the average grain size＜50μm.
We produce FeCoTaZr alloy sputtering target, it’s most important benefits is that in the process of PVD, the higher permeability can make the target sputtering smoothly and obtain the film with the smallest particles with uniform grains.
1. Metallic elements were analyzed by GDMS and ICP-OES.
2. Gas elements were analyzed by LECO.
3.The permeability was tested using permeability tester.