Title :
Epitaxially Grown FCC/BCC/HCP Multi-Underlayers for High Performance Perpendicular Media
Author :
Choe, Gunn ; Xu, Xiaoyu ; Tang, Kai ; Bian, Xiaoping
Author_Institution :
Hitachi Global Storage Technol., San Jose, CA
Abstract :
In this study, a new underlayer structure consisting of FCC NiW, BCC Cr and HCP Ru layers is investigated as a promising underlayer that offers good perpendicular magnetic and recording properties. The FCC (111) planes of NiW layer enhances hetero-epitaxial growth of the subsequent BCC Cr (110), HCP Ru and Co (0002) layers in the direction perpendicular to the film plane. After the NiW-Cr-Ru layer structure is optimized, the Co (0002) c axis dispersion is greatly reduced and ~ 3 degree of XRD rocking width is achieved. As a result, excellent magnetic properties such as high coercivity, high nucleation field and narrow switching field distribution (SFD) are obtained. In addition, low media jitter and high signal-to-media noise (SNR m) can be achieved. The SNR m is also highly dependent on head-to-SUL spacing which is altered by varying NiW or Cr layer thickness without affecting crystallography. Optimized head-to-SUL spacing is needed to gain head writeability as well as resolution.
Keywords :
chromium; coercive force; epitaxial growth; magnetic multilayers; magnetic switching; magnetic thin films; nickel alloys; perpendicular magnetic recording; ruthenium; tungsten alloys; FCC/BCC/HCP multiunderlayers; NiW-Cr-Ru; coercivity; crystallography; epitaxial growth; head writeability; nucleation field; perpendicular magnetic recording; signal-to-media noise; switching field distribution; FCC/BCC/HCP underlayer; head-to-SUL spacing; magnetic thin films; perpendicular magnetic recording;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2008.2002391