Electron spin resonance of the intermetallic antiferromagnet EuIn ₂As ₂

We present electron spin resonance (ESR) measurements in single-crystalline samples of EuIn ₂As ₂ grown using the In-flux method. This compound crystallizes in a hexagonal P6(3)/mmc structure and presents antiferromagnetic (AFM) ordering below T _N=16 K. In the paramagnetic state, a single Eu2 ⁺ Dysonian ESR line with nearly temperature-independent g-factor and linewidth is observed, indicating the absence of Korringa-like relaxation of the Eu2 ⁺ ions. Approaching the AFM transition, we observe an anisotropic g-shift and a linewidth broadening which has a maximum at T _N, suggesting that the short-range AFM correlation dominates the spin dynamics of the Eu2 ⁺ spins in this temperature range. Our results are discussed based on complementary data (magnetic susceptibility, heat capacity, and electrical resistivity measurements) that provide further details about the global macroscopic physical properties of the EuIn ₂As ₂ intermetallic compound.