Recording performance and magnetization switching of CoTb/CoCrPt composite perpendicular media

Abstract

Magnetic properties, recording performance, and thermal stability of CoTb amorphous/CoCrPt granular composite media are discussed. Thermal stability at low recording density of the composite media with CoCrPtB improves significantly as CoTb thickness increases, in accord with the increase of loop squareness, Mr/Ms. The media having CoTb thickness of more than 6 nm show almost no signal decay. Moreover, the signal-to-medium-noise ratio, SNR, improves with increasing CoTb thickness up to 6 nm. CoTb(6 nm)/CoCrPtB(20 nm) medium shows the best SNR performance under the present experimental conditions with no thermal decay. Media noise of the composite media with CoCrPt increases super linearly from ∼300 kfci, which is caused by the percolation of the recorded bits, probably due to the strong exchange coupling in the CoTb layer. The media with CoCrPtB shows less media noise than that with CoCrPt, and the super-linear increase of this media noise starts at ∼400 kfci which is higher than that of the media with CoCrPt. It is thought that the well-segregated grain structure of CoCrPtB layer, having the enhanced and fine distribution of Ms, reduces the magnetic cluster size effectively, resulting in the reduction of the media noise.

Effective reduction of the coercivity for Co72Pt28 thin film by exchange coupled Co81Ir19 soft layer with negative magnetocrystalline anisotropy

“…J e is the exchange constant and θ i indicates the angle between the magnetic moments and the external filed. In addition, demagnetizing energy was included properly in was taken from [27], CoPt-SiO 2 was taken from [26], CoCrPt was taken from [37], and Co 74 Pt 22 Ni 4 was taken from [28]. (b) Influence of the strength of the SL MA on the coercivity of the ECC media with a SL thickness of 5 nm.…”

Effective reduction of the coercivity for Co$_{72}$Pt$_{28}$ thin film by exchange coupled Co$_{81}$Ir$_{19}$ soft layer with negative magnetocrystalline anisotropy

“…CoPt-SiO2 was taken from Ref 26 ,. CoCrPt was taken from Ref 37 ,. and Co74Pt22Ni4 was taken from Ref 28.…”

Magnetization switching and thermal stability of CoCrPtB/CoDy composite perpendicular layer

“…6 The CoTb/CoCrPt composite perpendicular medium was reported to improve the thermal stability and SNR. 2,7 In this article, CoDy/CoCrPtB composite perpendicular coupled films were studied. The magnetization reversal process and magnetic properties of the coupled films were presented.…”