Planar patterned media fabricated by ion irradiation into CrPt3 ordered alloy films

Abstract

Planar patterned media using CrPt3 ordered alloy films were fabricated by Ar+ or Kr+ ion irradiation through nanoimprinted or electron beam lithography made masks. CrPt3 ordered alloy film on fused quartz substrate exhibits a large perpendicular anisotropy of 5×106 erg/cc and a large coercivity of 12 kOe, and we found that its magnetic order (magnetization) was completely suppressed by a quite low Ar+ or Kr+ ion dose of about 1–2×1014 ions/cm2. Magnetic force microscope image of the ion-beam patterned CrPt3 with a bit size of 90×90 nm showed clear magnetic contrast in nonirradiated regions, while no magnetic contrast in irradiated regions. The read-back waveform taken from an ion-beam patterned CrPt3 disk with 600 nm patterning pitch showed sharp signal transition between irradiated and nonirradiated regions, which indicates the possibility of high-density planar patterned media using CrPt3 ordered alloy.

Fabrication of [001] L1-FePtRh ferro-antiferromagnetic pattern by flat-patterning method

“…The first two methods involve the removal of the material between dots or the assembly of the particles, which leads to non-uniformity in the height of the disk surface and causes a head-floating problem for nearcontact recording. 1 However, in the last method, an FM film undergoes local changes to a soft magnetic, 5 paramagnetic (PM), 6 or antiferromagnetic (AF) 7 phase without surface asperity by ion irradiation or atomic diffusion.…”

Effects of lateral straggling of ions on patterned media fabricated by nitrogen ion implantation

“…In this method, tracks or bits are magnetically isolated by the area where the saturation magnetization (M s ) or the perpendicular anisotropy (K u ) are reduced by implanting non-magnetic ions. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] We previously reported that larger reduction of the M s in the ion-implanted area was important for obtaining higher signal quality. 15 On the other hand, a masked area needs to be protected from the process damages of the ion implantation.…”

Control of magnetic properties of MnBi and MnBiCu thin films by Kr+ ion irradiation

“…6 Recently, we have reported ion irradiation BPM using CrPt 3 ordered alloy films. [7][8][9] The CrPt 3 alloy film has a large perpendicular magnetic anisotropy, 10,11 and the magnetization of CrPt 3 can be suppressed by a quite low dose of ion irradiation associated with the phase change from ordered L1 2 to disordered A1 phases. Thus, the CrPt 3 is considered to be a candidate of high-density ion irradiation BPM with magnetically isolated bits.…”

“…Thus, the CrPt 3 is considered to be a candidate of high-density ion irradiation BPM with magnetically isolated bits. 7 However, high-temperature heat treatment at 850 C is required to synthesize the L1 2 CrPt 3 , which is a problem for the practical application of CrPt 3 .…”