Exchange-bias systems with compensated interfaces

Abstract

When a ferromagnetic metal (F) is in contact with an antiferromagnet (AF), often a shift of the hysteresis loop away from its normal, symmetric position around H=0, to HE≠0 does occur. This phenomenon is known as exchange bias (EB). We put forward an analytic model, for compensated AF interfaces, based on the AF interface freezing into a metastable canted spin configuration. The EB energy is reversibly stored in a spring-like magnet, or incomplete domain wall, in the F slab. Our theory yields the right values of HE and its F thickness dependence HE∝tF−1. It also predicts the F layer by layer magnetization profile.

Influence of in-plane crystalline quality of an antiferromagnet on perpendicular exchange coupling and exchange bias

“…More recent studies removed this constraint and found that spin-flop coupling would enhance the coercivity of the F thin film via an increase in uniaxial anisotropy, but did not produce exchange bias. Rather, a canted magnetic structure of the AF at the F-AF interface in combination with an incomplete domain wall in the F, 19 or uncompensated moments in the AF ͑Ref. 20͒ were required to produce exchange bias.…”

Tailoring exchange bias with magnetic nanostructures

“…1 In the exchange bias phenomenon in antiferromagnet/ferromagnet ͑AF/FM͒ bilayers, 2,3 one characteristic length scale is the size of the magnetic domains in both FM ͑ϳ1 m͒ and AF ͑much smaller͒, which are believed crucial to the mechanism. [4][5][6][7][8][9][10] Different types of domain models, with domain walls perpendicular or parallel to the interface, have been proposed. 4,5,9 Studying exchange bias in nanostructured AF/FM bilayers with nanoscopic feature sizes has the unique advantage of probing the role of domain size and morphologies.…”

“…[4][5][6][7][8][9][10] Different types of domain models, with domain walls perpendicular or parallel to the interface, have been proposed. 4,5,9 Studying exchange bias in nanostructured AF/FM bilayers with nanoscopic feature sizes has the unique advantage of probing the role of domain size and morphologies. It is also technologically important as the exchange bias in AF/FM nanostructures provides an additional, tunable source of anisotropy to stabilize the magnetization, therefore possibly reducing the length scale that determines the superparamagnetic limit in magnetic recording.…”

Manipulation of competing ferromagnetic and antiferromagnetic domains in exchange-biased nanostructures

“…Most theoretical models assume a well-established, temperature-dependent AF spin configuration that is different between polycrystalline or epitaxial materials, compensated or uncompensated interfaces, low or high AF anisotropy [16][17][18][19][20][21]. Furthermore, the AF domain structure has been so far mostly assumed to be insensitive to the neighboring FM, i.e.…”