Abstract
We report temperature dependent X-Band (ν≈ 9.5 GHz) Electron Spin Resonance (ESR) on the GdCuBi2 intermetallic compound. This compound presents a metallic Curie–Weiss paramagnetic behavior at high temperatures and orders antiferromagnetically at TN = 14.3 K. Well above TN (T > 250 K), the ESR experiments revealed temperature independent g-values spectra composed of a single Dysonian Gd3+ ESR line for the studied compound. Within the same temperature range, the Gd3+ ESR linewidth ΔH presents a linear broadening temperature dependence known as Korringa behavior. The obtained Korringa rate (ΔH/ΔT) and g-shift (Δg) from the ESR measurements, along with the study of the macroscopic properties of GdCuBi2 (e.g. specific heat data and magnetic susceptibility) made it possible to explore Gd3+ spin dynamics in this system based on evaluation of the exchange parameters between the Gd3+ ESR probes and the conduction-electrons (ce) in this compound. Our results indicate that the exchange bottleneck effects and a q-dependent exchange interaction (Jfs(q)) between the Gd3+4f and the ce are likely to be present in GdCuBi2. Disregarding the bottleneck effects in the simplest approximation, we extract the exchange parameters Jfs(q=0) ≈ 380 meV and <Jfs2(q)>1/2≈ 3.0 meV for the Gd3+ spin dynamics in GdCuBi2. These values of Jfs(q) and <Jfs2(q)>1/2 are typical of Gd3+ local moments in intermetallic materials and the small ratio [<Jfs2(q)>/Jfs2(0)] ≈ 0.008 suggests a strongly anisotropic (or quasi-2D) Fermi surface for GdCuBi2.
Original language | English |
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Article number | 172651 |
Journal | Journal of Magnetism and Magnetic Materials |
Volume | 613 |
DOIs | |
State | Published - Feb 1 2025 |