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Zusammenfassung:
Tb for Ca substituted hydroxyapatite ceramic samples with composition Ca10-xTbx(PO4)(6)(OH1-x/2-)(2), where x = 0.1, 0.5, were synthesized by solid-state reaction at 1300 degrees C in air, and their crystal structure, vibrational spectra, luminescence, and magnetic properties were studied. Implanting Tb3+ into the calcium apatite crystal lattice results in formation of an effective TbO+ ion which displays a short terbium-oxygen bond of 2.15 angstrom and a stretching vibration at 534 cm(-1). The Tb3+ electronic structure has been revealed by analyzing the luminescence spectra and dc/ac magnetization data. Accordingly, the ground state represents a pseudo doublet with M-J = +/- 6 and the first exited level is by 112 cm(-1) higher in energy. The ion exhibits field induced magnetic bistability with the magnetization reversing over the first exited state. Three paths of magnetization relaxation with field-temperature controlled switching between the paths have been identified.
