Short-range magnetic correlations in Tb5Ge4

TL;DR

This study investigates magnetic short-range correlations in Tb$_5$Ge$_4$ using neutron diffraction, revealing diffuse scattering indicative of three-dimensional clustering and potential Griffiths-like phase behavior.

Contribution

First detailed neutron diffraction analysis of short-range magnetic correlations in Tb$_5$Ge$_4$, highlighting complex clustering and diffuse scattering patterns.

Findings

Diffuse scattering observed both below and above T_N

Magnetic correlations form strongly coupled ferromagnetic blocks

Evidence of three-dimensional short-range magnetic correlations

Abstract

We present a single crystal neutron diffraction study of the magnetic short-range correlations in Tb$_5$Ge$_4$ which orders antiferromagnetically below the Neel temperature $T_N$ $\approx$ 92 K. Strong diffuse scattering arising from magnetic short-range correlations was observed in wide temperature ranges both below and above $T_N$. The antiferromagnetic ordering in Tb$_5$Ge$_4$ can be described as strongly coupled ferromagnetic block layers in the $ac$-plane that stack along the b-axis with weak antiferromagnetic inter-layer coupling. Diffuse scattering was observed along both $a^*$ and $b^*$ directions indicating three-dimensional short-range correlations. Moreover, the $q$-dependence of the diffuse scattering is Squared-Lorentzian in form suggesting a strongly clustered magnetic state that may be related to the proposed Griffiths-like phase in Gd$_5$Ge$_4$.