Spin disclination in a layered antiferromagnet with a screw dislocation

Flexomagnetism and vertically graded Néel temperature of antiferromagnetic Cr2O3 thin films

“…This effect is not addressed in the present work, although we anticipate that NV magnetometry of thin films of Cr 2 O 3 should be able to provide insight into this physics. Accessing this magnetization is crucial for the proper description of the physics of antiferromagnetic solitons, including domain walls, skyrmions, and disclinations 44 , 45 . Furthermore, our work poses questions on the magnetoelectric responses of these inhomogeneously strained thin films of Cr 2 O 3 .…”

Spin Dynamics in Antiferromagnets with Domain Walls and Disclinations

“…This size is maximum for the example of the layered AFM given above: in that case, ∼ √︀ ip / op , where is the interatomic distance. For typical values of the ratio op / ip ∼ 10 −2 , we obtain the -value of an order of tens of interatomic distances [76]. Beyond this region, the local vector l can be introduced as the difference between the vectors of the spins coupled by the antiferromagnetic interaction.…”

“…op ≫ ip . If such an AFM contains a screw dislocation, the atomic plane transforms into a helical surface (similar to the Riemann surface of the complex-valued function = ln ), the whole picture being far, at first glance, from the standard sublattice scheme [76]. However, a corresponding analysis showed that deviations from the standard "sublattice" picture of the AFM arise only in a small vicinity (with the size < ) of the dislocation line.…”

“…The static energy of the AFM contains a large number of invariants constructed from the components of the vectors m and l, as well as their gradients. If the states for which |m| ∼ |l| have to be taken into accounte.g., near the dislocation -the analysis becomes much more complicated, but it can also be carried out in some cases (see works [76,[78][79][80][81][82][83][84][85][86] and monographs [87,88]). In the standard Heisenberg AFM far from the dislocation and in a not very strong magnetic field, we may put |m| ≪ |l| ≃ 1 (for details, see work [76]).…”

“…If the states for which |m| ∼ |l| have to be taken into accounte.g., near the dislocation -the analysis becomes much more complicated, but it can also be carried out in some cases (see works [76,[78][79][80][81][82][83][84][85][86] and monographs [87,88]). In the standard Heisenberg AFM far from the dislocation and in a not very strong magnetic field, we may put |m| ≪ |l| ≃ 1 (for details, see work [76]). In this case, we can exclude the vector m and write the energy in terms of only the vector l = L/ |L| ≃ L/(2 0 ), assuming the latter to be a unit one.…”