Emergent Anomalous Hall Effect in the Eu-Based Compound with a Diamond Network: The Centrosymmetric Cubic Antiferromagnet EuTi$_2$Al$_{20}$

TL;DR

This study reports an emergent anomalous Hall effect in EuTi$_2$Al$_{20}$, a centrosymmetric antiferromagnet with a diamond lattice, revealing a possible topologically nontrivial spin texture in a field-induced phase.

Contribution

It uncovers a novel field-induced phase in EuTi$_2$Al$_{20}$ exhibiting enhanced Hall signals, suggesting a new type of topological spin texture beyond skyrmions.

Findings

Enhanced Hall resistivity in Phase II

Field-independent transport properties within Phase II

Moderate directional dependence of transport response

Abstract

The centrosymmetric cubic compound EuTi$_2$Al$_{20}$, in which magnetic Eu ions form a diamond network, undergoes an antiferromagnetic transition at T$_N$ = 3.3 K and exhibits metamagnetic transitions at H$_{m1}$ = 1.7 T and H$_{m2}$ = 2.8 T for H || [100] at 1.9 K. Between these fields, the magnetization shows a step-like behavior, defining an intermediate field-induced phase (Phase~II). We investigated the electronic transport in Phase~II and found that both the resistivity and Hall resistivity are markedly enhanced, while remaining nearly field independent within the phase. Phase~II appears for all field directions, although its transport response shows moderate directional dependence. These features differ from the strongly orientation-selective behavior often observed in skyrmion-lattice phases of several 4f-electron compounds, suggesting that Phase II may host a field-induced spin texture with a topological character distinct from that of a conventional skyrmion lattice.