Enhanced exchange bias in IrMn/CoFe deposited on self-organized hexagonally patterned nanodots

Abstract

Exchange biased nanostructures of IrMn/CoFe were deposited on anodized alumina with hexagonally patterned nanodot surface structures. Nanodots with diameters of 20, 70, and 100 nm were fabricated to investigate the size effect on the magnetic properties. Magnetometry and the first-order reversal curve method revealed significant enhancements of the exchange bias and coercivity in the nanodots compared with flat films. The enhancements can be attributed to the effective reduction of ferromagnet domain sizes and increased random fields due to the nanostructure morphology and domain wall pinning by the boundaries between adjacent nanodots.

Thickness effect on the easy axis distribution in exchange biased Co/IrMn bilayers

“…Motivated by these ideas, modern granular models considering a distribution of the easy axes of AF grains, and direct coupling between independent AF grains and the FM film, have been further developed [9,10,11]. The reports showed the easy axis distribu-tions (EAD) are very useful to model the rounded shape of hysteresis loops [12,13,14]. However, despite the continued use of EAD, it is not yet clear how it is related to the texture of polycrystalline FM/AF interfaces.…”