Magnetic and magnetoelectric properties of the Tb$_{0.75}$Ho$_{0.25}$Fe$_{3}$(BO$_{3}$)$_{4}$ ferroborate

Single crystals of the Tb$_{0.75}$Ho$_{0.25}$Fe$_{3}$(BO$_{3}$)$_{4}$ ferroborate have been grown by the group method from a solution–melt based on bismuth trimolybdate. The magnetic and magnetoelectric properties of the ferroborate single crystals have been investigated in the temperature range from 4.2 to 300 K and in magnetic fields up to 9 T. Magnetically, this material is an antiferromagnet with the Néel temperature $T_N$ = 38.8 K and easy-axis anisotropy. The magnitude of the magnetoelectric polarization has been found to be more than 1.5–2.0 times greater than the sum of the polarizations induced by the magnetic field for the ferroborates TbFe$_{3}$(BO$_{3}$)$_{4}$ and HoFe$_{3}$(BO$_{3}$)$_{4}$, taken in the corresponding shares.