Forthcoming events 2001

Abstract

The magneto-optical spectra of the R₁ and R₂ lines of Cr³⁺ ions in alexandrite have been measured under hydrostatic pressures and magnetic fields up to 6 GPa and 15 T, respectively. The spins of the excited states, ²E, have the Heisenberg-type characters at atmospheric pressure, though the g-values are anisotropic with the values between 1.3 and 2.0. The g-values for the direction parallel to the α-axis remain unchanged with increasing pressure, while for the directions normal to the α-axis they are reduced appreciably. The fine structure parameters of spins in the ground state, ⁴A₂, exhibit quite a similar behavior. The R₁-R₂ splitting is reduced also by pressure. These properties are the evidences that the spins of the ²E states become of the king-type under pressures above about 15 GPa. The mechanism of such the change of spin character is discussed quantitatively on the basis of a crystal field model.