Estimation of single-ion anisotropies, crystal-field and exchange interactions in Gd-based frustrated pyrochlore anti-ferromagnets Gd sub(2M) sub(2)O sub(7 (M=Ti, Sn, Hf, Zr))

• Published in: Journal of magnetism and magnetic materials Vol. 323; no. 24; pp. 3202 - 3209
• Main Authors: Biswas, AAli, Jana, Y M
• Format: Journal Article
• Language: English
• Published: 01.02.2011
• Subjects: Anisotropy; Approximation; Magnetic permeability; Magnetism; Mathematical analysis; Pyrochlores; Temperature dependence; Tensors
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2011.07.007

The temperature dependence of the experimental results of dc (macroscopic) magnetic susceptibility and nuclear hyperfine properties of frustrated magnetic Gd-based pyrochlore compounds, Gd sub(2Ti) sub(2)O sub(7, Gd) sub(2)Sn sub(2O) sub(7), Gd sub(2Hf) sub(2)O sub(7 and Gd) sub(2)Zr sub(2O) sub(7), are analyzed within the frame work of appropriate crystal-field theory and a mean field approximation by introducing effective anisotropic molecular field tensors, and formulating an exact relation between single-ion susceptibility tensors and site susceptibility tensors. Components of the calculated susceptibility along and perpendicular to the local [left angle bracket]1 1 1[right-pointing angle bracket] axis of the tetrahedral sublattice of pyrochlore structure show that these pyrochlores are easy-planar anisotropic magnetic systems. The crystal-field parameters and anisotropic exchange coupling have been determined and their systematic variations over the Gd-based pyrochlores studied here are discussed.