Neutron scattering experiments have been carried out that reveal the magnetic excitation in the ferromagnet CeAgSb2. Crystalline electric field excitations were observed at 5.2 and 12.5 meV in the paramagnetic state, indicative of the localized nature of the Ce 4f electron. Our analysis concluded that |Jz = ±1/2〉 is the ground state, while the first and second excited levels are mainly due to |±3/2〉 and |±5/2〉, respectively. The observed ferromagnetic moment is in good agreement with the ground-state saturation moment, gJμB Jz ∼ 0.43 μB. The spin wave dispersion is interpreted using the anisotropic Heisenberg model with ferromagnetic exchange interaction up to seventh-nearest neighbours. The spontaneous moment along the c-axis decreases with increasing field perpendicular to the c-axis, and disappears at the critical field Hc, which corresponds to the anomaly which appeared in the magnetization curve.
ASJC Scopus subject areas
- Condensed Matter Physics
- Electronic, Optical and Magnetic Materials