Temperature and pressure dependences of EPR spectra of Gd3+ ion doped in the EuAl3(BO3)4 monocrystal

The ground state of Gd3+ ions substituting for trivalent europium in the EuAl3(BO3)4 single crystal was studied by electron paramagnetic resonance (EPR) over the temperature range of 300–4.2 K and at pressures up to 9 kbar. The EPR spectra were analysed using the spin Hamiltonian of axial symmetry. The following parameters are reported: g=1.981±0.002, b20=280.18±0.12, b40=−12.95±0.08 and b60=0.61±0.12 (at Т=298 K). The distortions of the nearest environment of Gd3+ ion were analysed within the framework of the superposition model of crystal field.

► Parameters of EPR spectrum of Gd3+ ion replacing Eu3+ ion in EuAl3(BO3)4 crystal.
► Interaction of paramagnetic ion with nuclear moments of boron and aluminium atoms.
► The b20 parameter of spin Hamiltonian and the bond angle depend on pressure.
► Change in the bond angle contributes basically to change in the b20 parameter.