Electron spin resonance of the half-Heusler antiferromagnet GdPdBi

We present electron spin resonance (ESR) measurements at X-Band frequency (ν=9.5 GHz) in powdered single crystal of the half-Heusler antiferromagnet GdPdBi grown using a Bi-flux method. In the paramagnetic state, a single Gd ³⁺ Dysonian ESR line is observed with a nearly temperature independent g-factor of ≈1.99(2). On the other hand, the ESR linewidth ΔH increases non-linearly with decreasing temperature, indicating that the dominant relaxation mechanism occurs via Gd³⁺ spin-spin interaction. Approaching the AFM transition at T_N ≈13 K, the Gd³⁺ ESR line shifts to higher fields due to the emergence of short-range AFM correlations. Complementary data from macroscopic measurements such as magnetic susceptibility, heat capacity and electrical resistivity measurements provide further details about the global macroscopic physical properties of the GdPdBi compound.