Electronic and magnetic properties of 2H−NbS2 intercalated by 3d transition metals

Abstract

The electronic structure and magnetic properties of the 2H-NbS2 compound intercalated by Cr, Mn and Fe, have been investigated by means of the Korringa-Kohn-Rostoker (KKR) method. The calculations demonstrate easy plane magneto-crystalline anisotropy (MCA) of Cr 1/3 NbS2 monotonously decreasing towards the Curie temperature in line with the experimental results. The modification of the electronic structure results in a change of the easy axis from in-plane to outof-plane. It is shown, that for Cr 1/3 NbS2 and Mn 1/3 NbS2 the in-plane MCA and DzyaloshinskiiMoriya interactions results in a helimagnetic structure along the hexagonal c axis, following the experimental observations. The negative exchange interactions in the Fe 1/3 NbS2 compound results in a non-collinear frustrated magnetic structure if the MCA is not taken into account. It is shown, however, that a strong MCA along the hexagonal c axis leads to a magnetic ordering referred to as an ordering of the third kind, which was observed experimentally.

Half-magnetization plateau and the origin of threefold symmetry breaking in an electrically switchable triangular antiferromagnet

“…To capture the remaining fine features of Fe 1/3 NbS 2 would require a more sophisticated 3D model with vastly more parameters and temperature effects, similar to those in Refs. [6,10]. Nevertheless, as a minimal model that only includes a subset of the degrees of freedom, the model is highly consistent with measurements and seems to have identified the dominant interactions responsible for the magnetization response of Fe 1/3 NbS 2 .…”

“…This behavior has been seen with considerably lower energy requirements in Fe 1/3 NbS 2 as compared to the other systems [3], raising the question of whether the mechanism differs significantly [4,5]. At the center of this question is the nature of the magnetic ground state, which has been challenging to determine because collinear and noncollinear order are energetically close and the true ground state depends strongly on the magnetocrystalline anisotropy [6]. The nature of the underlying ordering in Fe 1/3 NbS 2 has been studied by both neutron scattering [7,8] of magnetic order and optical linear birefringence microscopy [9], which probes nematic structure in the electrical conductivity.…”

Origins of anisotropic transport in the electrically switchable antiferromagnet Fe1/3NbS2

“…We find for both sets of PBE+U calculations that the inplane and interplanar nearest-neighbor exchange constants J 1 and J 1c are antiferromagnetic (J > 0) and significantly larger in magnitude than the other three exchange constants, J 2 , J 2c , and J 3c (which are all ferromagnetic, J < 0). We note that this is also qualitatively consistent with a previous DFT study of the exchange constants in Fe 1/3 NbS 2 with no Hubbard U correction (U = 0 eV) [32]. Focusing on the experimentally relevant a-stripe and a-zigzag phases, the difference in energy between a-stripe and a-zigzag phases using the above equation is given by…”

Annihilation and Control of Chiral Domain Walls with Magnetic Fields

“…The spatial extent of the spin textures in LTEM, confirmed by SANS data, is hundreds of nanometers indicating a small DMI, which is much smaller than was observed in isostructural Cr 1/3 NbS 2 and is in agreement with electronic structure calculations. 40 The implication of these observations is that the DMI and the magnetostatic interactions are of similar magnitude so that variations within our samples, such as the sample thickness and crystalline disorder, although thought to be small, create significant variations in the periodicity of the spin textures. For the thin lamella explored through Fresnel images, the shape anisotropy appears to be sufficient to distort the magnetic structure, such that it is no longer helical, as the images suggest that regions where the magnetic moments lie within the plane of the lamella increase significantly for our thinnest samples.…”