Propagation of defects in doped magnetic materials of different dimensionality

TL;DR

This study investigates how defects affect magnetic properties in doped materials of different dimensions using neutron spectroscopy, revealing local exchange variations and displacement decay patterns.

Contribution

It provides detailed experimental evidence on defect propagation effects in 2D and 3D magnetic compounds, supporting theoretical displacement decay models.

Findings

Local exchange interactions deviate up to 10% from the average.

Mn-Mn distances vary stepwise with internal pressure.

Displacement decay follows 1/r^2, 1/r, and constant patterns for 3D, 2D, and 1D materials.

Abstract

Defects intentionally introduced into magnetic materials often have a profound effect on the physical properties. Specifically tailored neutron spectroscopic experiments can provide detailed information on both the local exchange interactions and the local distances between the magnetic atoms around the defects. This is demonstrated for manganese dimer excitations observed for the magnetically diluted three- and two-dimensional compounds KMn(x)Zn(1-x)F(3) and K(2)Mn(x)Zn(1-x)F(4), respectively. The resulting local exchange interactions deviate up to 10% from the average, and the local Mn-Mn distances are found to vary stepwise with increasing internal pressure due to the Mn/Zn substitution. Our analysis qualitatively supports 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.