Local Magnetic Fields in Some Bismuth-Based Diamagnets

Evidence that local ordered magnetic fields from 30 to 250 G exist in bismuth-based diamagnetic compounds comprising neither d- nor f-elements was given by ²⁰⁹Bi NQR spectroscopy and supported by SQUID measurements of α-Bi₂O₃. The NQR experiments involved a study of the zero-field line shapes, analysis of the Zeeman-perturbed patterns, and examination of the zero-field spin-echo envelopes in single crystals and powders. The results of the experiments followed by computer modeling of the observed spectra were interpreted assuming that ordered magnetic fields are located at the bismuth sites in α-Bi₂O₃, Bi₃O₄Br, Bi₂Al₄O₉, Bi₄Ge₃O₁₂, Bi₂Ge₃O₉ and perhaps in Bi₃B₅O₁₂. A survey of the related ²⁰⁹Bi NQR data is here presented.