Fluctuation field and time dependence of magnetization in TbFeCo amorphous rare earth-transition metal thin films for perpendicular magnetic recording

Abstract

In this work we report on the experimental analysis of the time decay of magnetization in the films of amorphous TbFeCo alloys for perpendicular magnetic recording. It is shown that the experimental results can be explained on the basis of the thermally activated incoherent subnetwork magnetization reversal model. Thermally activated reversal of the transition metal subnetwork and associated reversal of the antiferromagnetically coupled rare-earth subnetwork may result in effective stabilization of the net film magnetization. Experimentally obtained activation diameter value Da∼5–6 nm corresponds to the exchange length or the domain wall width in the films under study. The small activation diameter value combined with high stability factor k∼250 mean that the TbFeCo amorphous film should be capable of supporting a thermally stable perpendicular recording at over 100 Gbit/in2 recording density.

Magnetic and anomalous magnetic viscosity in the bulk amorphous ferromagnet and partially amorphous ferromagnet

“…The plot of m 0 H a as a function of lnðt i Þ results in a straight line whose gradient (from Eq. (2) 18 . Indeed from the magnetic viscosity data it appears that a level of crystallinity of % 40% has little impact on the observed magnetic relaxation behaviour.…”

TbFeco film with W underlayer and overlayer for perpendicular magnetic recording

“…The feasibility of 450 kfci perpendicular magnetic recording and its thermal stability were recently demonstrated [1,2]. TbFeCo film is extremely susceptible to oxidation and its saturation magnetization is very small near room temperature [3,4].…”

Magnetic properties of co-sputtered Tb–Co2FeAl films with perpendicular anisotropy

“…vortex magnetization or magnetic curling at the edge of the films) if the films are patterned into nanoscale devices and lead to memory cell instability or switching field fluctuation [6,7]. However, those problems could be solved using magnetic thin films with perpendicular magnetic anisotropy (PMA), for example, amorphous rare-earth transition-metal (RE-TM) compounds [8][9][10], (Co/Pd) n , (Co/Pt) n , and (Co/Ni) n multilayers [11][12][13]. For the RE-TM films, coercivity field (H C ) is usually too large to be used in the high sensitive sensors.…”