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

Abstract

Antiferromagnetically coupled (AFC) patterned media technology is one approach to reduce dipolar interactions and thus minimize the switching field distribution (SFD) in bit-patterned media. Achieving anti-parallel alignment of magnetic moments at remanence requires a large exchange coupling field (H ex ), especially in patterned nanostructures, which exhibit a large enhancement in coercivity after patterning. In our work, we observed a very high H ex of more than 15 kOe in Co thin film antiferromagnetically coupled to (Co/Pd) multilayers with a high perpendicular magnetic anisotropy (PMA). In contrast, an H ex of only 380 Oe was measured in the case of (Co/Pd) multilayers of the type [Co (0.4 nm)/Pd (0.8 nm)] 3 antiferromagnetically coupled with (Co/Pd) multilayers with a high PMA. The effect of H ex on SFD of patterned structures was investigated, and it was found that SFD can be reduced in AFC patterned films with a high H ex .

Demagnetizing factors in patterned CoNiFe films with rectangular elements

“…Magnetic arrays with micron and submicron elements have attracted a lot of attention recently due to their potential applications in magnetic random access memory (MRAM) and ultrahigh-density data storage, [1][2][3][4] as well as their unique behaviors. For continuous magnetic polycrystalline thin films, the magnetic anisotropy in the film plane is often negligible, but it becomes significant in patterned films as the lateral size of the elements in it decreases, which influences other properties such as hysteresis loop, coercivity, remanence, and saturation field.…”