EPR of Non‐Kramers Rare‐Earth Ions in Tetragonal Crystals

Electric Δ M = 0 and magnetic Δ M = 0 and Δ M = 1 transitions were measured with X‐, K‐, and Q‐band frequencies within the ground state doublets of the rare‐earth ions in (Y, Tb)PO 4 , (Y, Tm)VO 4 , (Y, Tm)AsO 4 , and (Y, Ho)AsO 4 . The g ‐factors and hyperfine constants were determined. The doublets show a zero field splitting Δ which can be attributed to random strain. The half width of the distribution of the splitting Δ, the most probable splitting, and the natural line width were evaluated from the line shape and line position. The intensities of the electric transitions were compared with those of a crystal field calculation.