Linear magnetoresistance, anomalous Hall effect and de Haas-van Alphen oscillations in antiferromagnetic SmAg$_2$Ge$_2$ single crystals

TL;DR

This study reports the growth and investigation of SmAg$_2$Ge$_2$ single crystals, revealing complex electronic behaviors such as linear magnetoresistance, anomalous Hall effect, and quantum oscillations linked to its antiferromagnetic order.

Contribution

It provides the first comprehensive experimental and theoretical analysis of SmAg$_2$Ge$_2$, highlighting its electronic structure and magnetic properties in relation to complex phenomena.

Findings

Linear non-saturating magnetoresistance of ~97% at 2K

Significant anomalous Hall effect with Hall angle 0.10-0.14

Observation of de Haas-van Alphen quantum oscillations above 8T

Abstract

Understanding the interplay among magnetism, electron correlations, and complex electronic structures in rare-earth materials requires both high-quality single crystals and systematic investigation of their electronic properties. In this study, we have successfully grown a single crystal of SmAg$_2$Ge$_2$ and investigated its anisotropic physical properties and de Haas-van Alphen (dHvA) quantum oscillations through experimental and theoretical approaches. SmAg$_2$Ge$_2$ crystallizes in the well known ThCr$_2$Si$_2$-type tetragonal structure with lattice parameters, $a~=~4.226$~\AA~ and $c~=~11.051$~\AA. Electrical transport and magnetization measurements indicate that it is metallic and exhibit antiferromagnetic ordering below the N\'{e}el temperature, $T_{\rm N}$ = 9.2~K. SmAg$_2$Ge$_2$ exhibits a linear non-saturating magnetoresistance, reaching $\sim 97$\% at $2$~K for applied magnetic field $B$~$\parallel~[001]$ and a significant anomalous Hall effect with an anomalous Hall angle of $0.10-0.14$. Additionally, magnetization measurements reveal dHvA quantum oscillations for magnetic fields greater than $8$~T. Our calculated electronic structure, quantum oscillations, and anomalous Hall effect in the canted antiferromagnetic state closely align with experimental results, underscoring the role of complex electronic structure and spin-canting-driven non-zero Berry curvature in elucidating the physical properties of SmAg$_2$Ge$_2$