Effects of grain size and intergranular coupling on recording characteristics in CoCrTa media

The role of NiAl underlayers in longitudinal thin-film recording media

“…Media magnetic properties are strongly influenced by the Cr grain size and the epitaxy between the Cr and the Co, which itself depends upon the Cr film, the Co alloy Cr lattice mismatch 2 and sputter process variables such as base pressure. 3,4 Alternative underlayer materials to control the Co grain size and epitaxy are therefore of interest. Most work has focused on improving the Co-alloy lattice match with different bcc alloys of Cr, including CrCo, 5 CrMo, CrTi, and CrV.…”

Magnetic Microstructure and Media Noise of Thin Film Media Fabricated under Ultra Clean Sputtering Process

“…Here, the value ofCV MFM -signal is defined as the ratio of standard deviation of MFM signals to averaged MFM signal at transitions. This value of CVMFM-signal corresponds to the degree of dispersion of magnetic field strength at transitions, which decreases in accordance with the decreasing the dispersion of magnetic field strength at transitions [7].…”

“…To reduce the media noise which is strongly correlated to the microstructure of the film is essentially required for thin film media to achieve high density magnetic recording. An ultra clean sputtering process (DC process) has been proposed to be a key technology to enable the enhancement of Cr segregation at grain boundary resulting in low intergranular exchange coupling [1][2][3][4][5][6][7][8][9]. As another technical merit, by decreasing underlayered Cr thickness, the UC process realizes the reduction of ferromagnetic grain size without the increment of intergranular exchange coupling.…”

“…As another technical merit, by decreasing underlayered Cr thickness, the UC process realizes the reduction of ferromagnetic grain size without the increment of intergranular exchange coupling. While, concerning the media noise, grain size reduction and also the decrement of intergranular magnetic coupling play an important role for improving recording performance [6,7,9].…”

Novel Magnetic Properties Introduced by Ultra Clean Sputtering Process

“…These interfacial and microstructural conditions, which affects strongly these physical properties through intergranular magnetic coupling, should be exactly controlled in fabrication process. We have been proposing the new concept in controlling the microstructure, defined as ultra clean sputtering process (UC-process) and showing the remarkable magnetic properties induced [1][2][3][4][5][6][7][8][9]. In this paper, the relation between the cleanness during film deposition process and magnetic properties is widely reviewed in connection with their microstructures.…”