Defect propagation in one-, two-, and three-dimensional compounds doped by magnetic atoms

TL;DR

This study investigates how magnetic atom doping causes defect propagation in 1D, 2D, and 3D compounds, revealing local structural inhomogeneities and their effects on magnetic excitations.

Contribution

It provides experimental evidence and statistical models describing defect-induced structural inhomogeneities and their impact on magnetic properties in doped compounds.

Findings

Observation of fine structures in neutron scattering spectra due to local inhomogeneities

Support for decay of atomic displacements as 1/r, 1/r^2, and constant in 3D, 2D, and 1D compounds

Determination of local exchange interactions and intradimer distances from spectral features

Abstract

Inelastic neutron scattering experiments were performed to study manganese(II) dimer excitations in the diluted one-, two-, and three-dimensional compounds CsMn(x)Mg(1-x)Br(3), K(2)Mn(x)Zn(1-x)F(4), and KMn(x)Zn(1-x)F(3) (x<0.10), respectively. The transitions from the ground-state singlet to the excited triplet, split into a doublet and a singlet due to the single-ion anisotropy, exhibit remarkable fine structures. These unusual features are attributed to local structural inhomogeneities induced by the dopant Mn atoms which act like lattice defects. Statistical models support the theoretically predicted decay of atomic displacements according to 1/r**2, 1/r, and constant (for three-, two-, and one-dimensional compounds, respectively) where r denotes the distance of the displaced atoms from the defect. The observed fine structures allow a direct determination of the local exchange interactions J, and the local intradimer distances R can be derived through the linear law dJ/dR.