Narrowing of antiferromagnetic domain wall in corundum-type Cr₂O₃ by lattice strain

Abstract

The effect of lattice strain on single-ion magnetic anisotropy and antiferromagnetic domain wall width in corundum-type Cr2O3 is studied using first-principles calculations and micromagnetics simulations. Without lattice strain, the domain wall width L DW is about 80 nm. When the lattice constant a is increased by 1–2%, L DW is reduced to less than 20 nm due to the increase in the single-ion anisotropy constant K 1 to on the order of 106 erg/cm3.

Control of lateral ferromagnetic domains in Cr2O3/Pt/Co thin film system with positive exchange bias

“…Designing these two intermediate state is required with respect to each applications. In fact, the magnetic domain of Cr2O3 received increasing attentions toward device applications; Experimental demonstration of a local writing of exchange biased domain of Cr2O3/FM heterostructure, 23 theoretical study on domain wall dynamics, 24 and domain wall width 25 were reported recently. However, thus far, there's no attempt to control these two state actively.…”

Magnonic topological insulators in antiferromagnets

“…Within the long wave-length approximation, it becomes γ 2 k = 1 − (ak) 2 /d for | k |= k and thereby assuming a spin anisotropy 67,68 at low temperature, the dispersion becomes parabolic in terms of k and reduces to the form ω k = Dk 2 + ∆ with D = JSa 2 / √ κ 2 + 2κ which is used in the main text. Note that the dispersion becomes linear in terms of k, ω k ∝ k, when there is no spin anisotropy K = 0, i.e., κ = 0.…”

“…where J > 0 parametrizes the antiferromagnetic exchange interaction between the nearest-neighbor spins and K > 0 is the easy-axis anisotropy 67,68 that ensures the magnetic Néel order along the z direction. Since the Hamiltonian is invariant under global spin rotations about the z axis, the z component of the total spin is a good quantum number (i.e.…”

“…(4c) satisfy the Onsager relation. In the absence of a magnetic field, B = 0, up and down magnons are degenerate and the degeneracy is robust against external perturbations due to the spin anisotropy 67,68 and the resultant magnon energy gap. This gives L ii↑ = L ii↓ , while L ij↑ = −L ij↓ for i = j because of the opposite magnetic dipole moment σ = ±1.…”

“…For an estimate, we assume the following experiment parameter values 67,68 for Cr 2 O 3 , J = 15meV, K = 0.03meV, S = 3/2, g = 2, E = 1V/nm 2 , and a = 0.5nm. This provides the Landau gap ω c = 1µeV and l E = 0.7µm [Eqs.…”