Large magnetoresistance and first-order phase transition in antiferromagnetic single-crystalline EuAg 4 Sb 2
Year: 2024
Type: article
Abstract: We present the results of a thorough investigation of the physical properties of ${\mathrm{EuAg}}_{4}{\mathrm{Sb}}_{2}$ single crystals using magnetization, heat capacity, and electrical resistivity measurements. High-quality single crystals, which crystallize in a trigonal structure with space group $R\overline{3}m$, were grown using a conventional flux method. Temperature-dependent magnetization measurements along different crystallographic orientations confirm two antiferromagnetic phase transitions around ${T}_{N1}=10.5\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ and ${T}_{N2}=7.5\phantom{\rule{0.16em}{0ex}}\mathrm{K}$. Isothermal magnetization data exhibit several metamagnetic transitions below these transition temperatures. Antiferromagnetic phase transitions in ${\mathrm{EuAg}}_{4}{\mathrm{Sb}}_{2}$ are further confirmed by two sharp peaks in the temperature-dependent heat capacity data at ${T}_{N1}$ and ${T}_{N2}$, which shift to lower temperature in the presence of an external magnetic field. Our systematic heat capacity measurements utilizing a long-pulse and single-slope analysis technique allow us to detect a first-order phase transition in ${\mathrm{EuAg}}_{4}{\mathrm{Sb}}_{2}$ at 7.5 K. The temperature-dependent electrical resistivity data also manifest two features associated with magnetic order. The magnetoresistance exhibits a broad hump due to a field-induced metamagnetic transition. Remarkably, the magnetoresistance keeps increasing without showing any tendency to saturate as the applied magnetic field increases, and it reaches $\ensuremath{\sim}20$ 000% at 1.6 K and 60 T. At high magnetic fields, several magnetic quantum oscillations are observed, indicating a complex Fermi surface. A large negative magnetoresistance of about $\ensuremath{-}55%$ is also observed near ${T}_{N1}$. Moreover, the $H\text{\ensuremath{-}}T$ phase diagram constructed using magnetization, heat capacity, and magnetotransport data indicates complex magnetic behavior in ${\mathrm{EuAg}}_{4}{\mathrm{Sb}}_{2}$.
Language: Latvian
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Award: G8152425740
OpenAlex ID: W4403587237