Exchange anisotropy and spin-wave damping in CoFe/IrMn bilayers

Abstract

Exchange bias of NiO/NiFe: Linewidth broadening and anomalous spin-wave damping J. Appl. Phys. 93, 7723 (2003); 10.1063/1.1557964 Kerr observations of asymmetric magnetization reversal processes in CoFe/IrMn bilayer systems

Broadband ferromagnetic resonance characterization of anisotropies and relaxation in exchange-biased IrMn/CoFe bilayers

“…determined from ferromagnetic resonance data, see figure 7. Due to the interfacial nature of the exchange bias effect the exchange bias field is expected to scale with the inverse of the thickness of the ferromagnetic layer [7,18,35], which is confirmed in figure 7. From the slope of this figure and the saturation magnetization determined earlier, one can determine the interface energy per unit area [7,36,37], also called interfacial exchange coupling, ∆ · · , which enables a comparison with other exchange bias systems.…”

“…If the unidirectional linewidth contribution was solely caused by a strictly interfacial two-magnon scattering one would expect it to be proportional to 1/ . This is because in this case the two-magnon scattering scales with the square of the scattering potential, which is proportional to the inverse of the ferromagnetic film thickness [9,17,18,21]. However, the blue fit curve in figure 11 a), which uses this relationship, results in a poor description of the data.…”

“…However, magnetization reversal measurements can be difficult to analyze quantitatively, in particular due to the complex phase diagrams [10,11] and the formation of complicated domain structures [12][13][14][15]. Here measurements of the magnetization dynamics, for example using ferromagnetic resonance [8,[16][17][18] or Brillouin Light Scattering [17][18][19], offer the advantage that they can be carried out at external magnetic fields sufficient to saturate the system. While most of the early work on magnetization dynamics of exchange bias systems focused on the determination of the unidirectional anisotropy to provide input to model development, it was also noted early on that the exchange bias effect has a profound influence on the magnetization relaxation in these systems [16,18].…”

“…Here measurements of the magnetization dynamics, for example using ferromagnetic resonance [8,[16][17][18] or Brillouin Light Scattering [17][18][19], offer the advantage that they can be carried out at external magnetic fields sufficient to saturate the system. While most of the early work on magnetization dynamics of exchange bias systems focused on the determination of the unidirectional anisotropy to provide input to model development, it was also noted early on that the exchange bias effect has a profound influence on the magnetization relaxation in these systems [16,18]. Two magnon scattering at the ferromagnet/antiferromagnet interface is one of the major contributions to the relaxation in these systems [9,17,20].…”

Effect of nanostructure layout on spin pumping phenomena in antiferromagnet/nonmagnetic metal/ferromagnet multilayered stacks

“…The linewidth of the FMR spectrum increases due to the presence of the AFM layer and thereby provides information about the interaction of the nonequilibrium conduction-electron spins and the localized AFM moments. The interpretation of such experiments is not quite straightforward, however, as different processes contribute to the effective damping in a multilayered sample: spin-dependent scattering at the interfaces 10 and in the bulk, energy exchange between the free and localised spins, spin-diffusion, etc. An efficient theoretical approach to this problem, based on nonequilibrium thermodynamics, was proposed in Ref.…”