Electron Spin Resonance (ESR) studies on GdCuBi2 intermetallic antiferromagnet

G. S. Freitas, H. Pizzi, F. B. Carneiro, M. H. Carvalho, E. M. Bittar, E. D. Bauer, J. D. Thompson, F. Ronning, S. M. Thomas, P. F.S. Rosa, S. M. Greer, P. G. Pagliuso

Research output: Contribution to journalArticlepeer-review

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 languageEnglish
Article number172651
JournalJournal of Magnetism and Magnetic Materials
Volume613
DOIs
StatePublished - Feb 1 2025

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