Medium noise and grain size analysis of CoCrPt/Ti perpendicular media with NiAl seed layer

Abstract

Perpendicular medium with an average grain size of 8.2 nm have been produced by using a-CoCrPt/Ti/NiAl tri-layer structure. The signal-to-noise ratio for the tri-layer medium is 2-7 dB higher than CoCrPt/Ti bi-layer medium at low deposition temperatures. The medium noise is dominated by dc noise and exhibits little transition noise for densities less than 500 kFCI. The ultra-small grain size will improve the performance of perpendicular media for future high-density recording applications.

Effects of thermal annealing on structural and magnetic properties of thin Pt/Cr/Co multilayers

“…However, since the mixing is not adequate, no signature of any mixed phase is detected in the corresponding XRD pattern. At the higher annealing temperatures of 773 and 873 K, the Pt and Co signals completely disappear and a new peak corresponding to the CoCrPt (0 0 0 2) reflection appears at 2y ¼42.51 [13][14][15][16]. Thus, it seems that at 873 K, complete mixing takes place amongst the constituent layers of Pt/Cr/Co ML structures, which is in good agreement with our XRR results discussed earlier.…”

Advancements in PMR thin-film media

“…In 2001, Ikeda et al [19] found that NiAl seed layers with Ti IL in CoCrPt (20 nm)/Ti (18 nm)/ NiAl (40 nm) at 230 1C gave H c ¼ 4000 Oe and reduced hDi ¼ 8:2 nm from 2000 Oe and 10.7 nm without NiAl since its B2 structure induced small decoupled grains that decreased transition noise but not DC noise in increasing the SNR.…”

Soft X-ray characterization of perpendicular recording media

“…3(b) is the grain diameter distribution giving the probability of a grain of diameter , which includes the width of the grain boundary. The solid line is a fit of to a log-normal distribution (2) where unit cells (vertical dashed line) is the mean grain diameter and is a dimensionless geometric standard deviation. Such a distribution is often used to describe experimentally observed grain-diameter distributions in recording media [1].…”

“…The granular microstructure limits the magnetic correlations to length scales comparable to the grain size and allows information to be written on a finer scale than possible in a homogeneous magnetic film. For perpendicular recording, this microstructure is currently achieved in -axis oriented CoCrPt alloy thin films [2] and more recently using CoX-Pd or CoX-Pt where or Cr [3]- [5]. Further improvements in recording performance are expected from improved growth conditions, improved underlayer structures, and the use of more complex alloys to reduce the grain size and intergranular coupling.…”

“…However, intergranular exchange can increase this length, which Manuscript is believed to be a key factor in the noise behavior. In this paper, we describe the emerging technique of resonant soft X-ray small-angle scattering (SAS) as a probe of the grain size, chemical segregation, and magnetic correlations in CoPtCr thin film and CoB-Pd multilayer recording media [2]- [4]. We will highlight the strong resonantly enhanced scattering from both the magnetic and chemical structure in media films and the applicability of resonant soft X-ray techniques for assessing future recording media, where grain sizes and magnetic correlations lengths 100 are anticipated [1].…”