Recording characteristics of perpendicular magnetic media with CoZrNb, NiFeNb, and exchange-pinned NiFeNb soft magnetic underlayers

Authors

Min Zheng, MMC Technology, Inc., San Jose, California
Albert Chekanov, MMC Technology, Inc., San Jose, California
Geon Choe, MMC Technology, Inc., San Jose, California
Kenneth E. Johnson, MMC Technology, Inc., San Jose, California
Lan Gao, University of Nebraska - Lincoln
Sy_Hwang Liou, University of Nebraska-LincolnFollow

Date of this Version

May 2003

Comments

Published by American Institute of Physics. J. Appl. Phys., 93, 6763 (2003). ©2003 American Institute of Physics. Permission to use. http://jap.aip.org/jap/.

Abstract

The recording performance of perpendicular media with amorphous CoZrNb, nanocrystalline NiFeNb, and exchange-pinned FeMn/NiFeNb soft magnetic underlayers (SULs) has been studied. A method has been proposed to quantify the spike noises from the SUL. We found that media with higher permeability NiFeNb SULs showed 4 db higher signal-to-noise ratio than media with lower permeability CoZrNb SULs. The exchange-pinned NiFeNb SUL suppresses spike noise and offers good recording performance. Furthermore, the recording frequency dependence of dynamic coercivity (H_c) was strongly affected by the use of different SULs. The increase in dynamic H_c with linear density is negligibly small for media with NiFeNb SULs, whereas dynamic H_c sharply increases with increasing density for media with CoZrNb SULs.