Role of the Antiferromagnetic Bulk Spin Structure on Exchange Bias

Simultaneous in-plane and out-of-plane exchange bias using a single antiferromagnetic layer resolved by x-ray magnetic circular dichroism

“…[4][5][6][7][8] Moreover, in FM/AFM/FM structures, simultaneous antiparallel or perpendicular IP H E of the two FM layers has been induced. [9][10][11] Similar states have been obtained in nanostructured exchange biased systems by exploiting shape anisotropy. 12,13 To date, although IP FM/AFM/FM systems have been widely investigated, [9][10][11]14 only a few studies have been performed on FM/AFM/FM coupling in OP systems.…”

“…[9][10][11] Similar states have been obtained in nanostructured exchange biased systems by exploiting shape anisotropy. 12,13 To date, although IP FM/AFM/FM systems have been widely investigated, [9][10][11]14 only a few studies have been performed on FM/AFM/FM coupling in OP systems. 15,16 The increase of perpendicularly magnetized elements in magnetic memories and tunnel junctions, 2,3 as well as the emergence of hybrid IP/OP devices [16][17][18] has recently exposed the need for simultaneously IP and OP exchange biased layers in a single structure.…”

“…Importantly, the H E of each layer is along its corresponding easy axis, implying that the AFM layer is capable of supporting uncompensated spins in orthogonal directions at the same time. Hence, either a complex AFM wall is formed in the AFM 10,11,14 or the uncompensated spins can be generated independently from each other at each interface. 9 Work supported by the Spanish MICINN ͑MAT2007-66309-C02͒, Catalan DGR ͑2009-SGR-1292͒, ERC ͑SG 203239͒.…”

Antiferromagnetic domain size and exchange bias

“…21 ͑4͒ The exchange bias in FM/AF/FM trilayers is strongly dependent on the relative magnetic state of the two FM's; thus, implying a strong coupling across the thick AF. 83 A different view-one wherein the AF bulk spin structure does influence H E -is that the AF domain state of the film bulk propagates to the FM/AF interface affecting the local domain state. For example, the size of the AF domains in the bulk may determine how many uncompensated magnetic spins are available ͑in the bulk and at the FM/AF interface͒ for aligning and pinning by the cooling field to produce H E .…”

Chirality Switching and Winding or Unwinding of the Antiferromagnetic NiO Domain Walls inFe/NiO/Fe/CoO/Ag(001)

“…However, a spring-like domain wall is not expected in the FeF 2 space layer due to its strong uniaxial magnetic anisotropy, i.e. the Mauri planar domain wall model cannot explain the exchange bias in this system [13]. The difficulty in explaining the above described experiments is due to the lack of a direct and element-specific measurement of the AFM spins which became possible only after the development of the X-ray Magnetic Linear Dichroism (XMLD).…”