High frequency (208 GHz) determination of the cubic spin Zeeman term for the U3+ ion in the dilute magnetic semiconductor crystals of Pb1−xUxTe and Pb1−xUxSe at 5 K by electron paramagnetic resonance

• EPR studies of U3+ ion done at 208 GHz at 5 K embedded in PbTe and PbSe crystals.
• Site symmetry at U3+ ion is determined to be cubic from EPR data.
• Zeeman cubic spin term parameter u=-0.0257 determined for both crystals.
• g=1.9811 Determined for both crystals.

A high-frequency (208 GHz) Electron Paramagnetic Resonance (EPR) study on the U3+ ion (5f3, 4I9/2, S=3/2) embedded with 3% concentration in the dilute magnetic semiconductor crystals of PbTe and PbSe, each characterized by cubic symmetry, has been performed at ~5 K, especially in view to determine the value of the Zeeman cubic spin term parameter u, and the site symmetry of the U3+ ion (radius 0.089 nm), substituting for the Pb2+ ion (radius 0.119 nm). The experimental spectra reveal the presence of only one set of EPR lines from U3+ ions in these host crystals, exhibiting cubic symmetry, whose magnetic axes are oriented along the crystal axes. The spin-Hamiltonian parameters are for both crystals: g=1.9811, u=-0.0257.