Paramagnetic Resonance Absorption of Nickel in Sapphire

Abstract

A paramagnetic resonance absorption spectrum which is in excess of that due to trivalent chromium and iron has been observed in sapphire single crystal. The spectrum is interpreted as being due to transitions between fine structure energy states of divalent nickel. Best fit constants to the spin Hamiltonian, obtained at room temperature, are given by D = [1.385±0.002] cm−1, g∥ = 2.196±0.004, and g⊥ = 2.187±0.004. Measurements made by progressive saturation of the resonance lines at 77 °K give an average spin-lattice relaxation time of 6 × 10−6 sec.