Magnetic properties of Pr2-x Fe1+x SbO7 and Bi2-x Ln (x) FeSbO7 (Ln = La, Pr) pyrochlore solid solutions

摘要

The Bi-La-Fe-Sb-O, Pr-Fe-Sb-O, and Bi-Pr-Fe-Sb-O systems have been shown to contain pyrochlore solid solutions. We have determined the limits of the Pr2-x Fe1 + x SbO7 and Bi2-x Ln (x) FeSbO7 (Ln = La, Pr) solid solutions and shown that there is no compound corresponding to the "ideal" composition Pr2FeSbO7. Analysis of the magnetic properties of the synthesized compounds indicates that rare earth substitution for bismuth ions has no effect on the spin glass transition and that the spin glass state is only determined by the interaction between the Fe3+ spins on the octahedral site. The Pr3+ paramagnetic ion in Pr2-x Fe1 + x SbO7 does not participate in the formation of the spin glass state but makes a paramagnetic contribution to the total magnetic susceptibility, which is especially significant at low temperatures.