Comparison of magnetic properties of GdFe$_3$(BO$_3$)$_4$ ferroborates grown using various solvents

GdFe$_3$(BO$_3$)$_4$, single crystals were grown from melt-solutions based on bismuth trimolybdate and lithium tungstate. Single crystals of gadolinium ferroborate from lithium-tungstate solution-melt were grown for the first time. The magnetic properties of the grown crystals are compared. It is shown that the GdFe$_3$(BO$_3$)$_4$, ferroborate obtained using bismuth solution-melt trimolybdate contains impurities of Bi$^{3+}$ ions (6% at.), which replace Gd$^{3+}$ ions. Whereas GdFe$_3$(BO$_3$)$_4$, ferroborate grown from a solution-melt based on lithium tungstate does not seem to contain such uncontrolled impurities.