Antiferromagnetically coupled capped bit patterned media for high-density magnetic recording

Abstract

We report micromagnetic modeling of a bit patterned media where a two-dimensional array of patterned composite islands is antiferromagnetically coupled to a continuous capping layer. This media allows optimization of writability, switching field distributions, and readback response. Lateral and vertical exchange introduced through the coupling with the capping layer compensates the dipolar interactions between islands and antiferromagnetic coupling is employed to modulate the high-density readback response.

Reversal in Bit Patterned Media With Vertical and Lateral Exchange

“…We show that in such media a simultaneous optimization for reduced SFDs and improved thermal stability 0018-9464/$26.00 © 2010 IEEE is possible. In the AFC-composite-CBPM (AFC-CCBPM) design, the capping layer may also be optimized to suppress magnetostatic interference effects in the readback response [26].…”

“…Effects of the capping layer on media stability and its optimization are examined. To achieve a maximum reduction in switching fields at minimal SFDs, ECC elements can be used in concert with the continuous capping layer [26] [ Fig. 1(e)].…”

Dipolar Antiferromagnetism and Quantum Criticality in LiErF 4

“…Indeed, an estimate of the h 4 anisotropy due to order-by-disorder is of the correct order of magnitude to yield β = 0.15 (see SOM for details). The long history of theoretical studies of the 2D dipolar-coupled rotor model was recently revived by advances in microfabricated artificial nanomagnet arrays, which are pursued both as model systems for fundamental physics (25) and for ultra-high-density magnetic storage technology (26,27). LiErF 4 , which we see falls into this universality class, now provides a bulk material with a fully determined Hamiltonian where theoretical predictions can be guided and tested.…”

Magnetic properties of antidots in conventional and spin-reoriented antiferromagnetically coupled layers

“…[3][4][5] One of the crucial challenges of BPM is the widening of the switching field distribution (SFD). [5][6][7][8][9] The write-in-error is highly influenced by the SFD, and therefore narrow SFDs within nano-patterned arrays are needed to record onto each individual bit reliably without disturbing the surrounding neighbors. [6][7][8][9][10] Recently, antiferromagnetically coupled (AFC) patterned media technology has been proposed to minimize SFD.…”

“…[5][6][7][8][9] The write-in-error is highly influenced by the SFD, and therefore narrow SFDs within nano-patterned arrays are needed to record onto each individual bit reliably without disturbing the surrounding neighbors. [6][7][8][9][10] Recently, antiferromagnetically coupled (AFC) patterned media technology has been proposed to minimize SFD. 9,10 In order to achieve antiferromagnetic coupling at remanence after patterning, it is a prerequisite that the exchange coupling field (H ex ) acting on the thinner layer be greater than its coercivity (H c ).…”