Crystal field levels and zero-field splitting parameters of Cr2+ in the mixed system Rb2MnxCr1−xCl4

✍ Scribed by Czeslaw Rudowicz; Maolu Du; Yau-yuen Yeung; Yi-yang Zhou

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 561 KB
• Volume: 191
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/0921-4526(93)90092-k

✦ Synopsis

The crystal field (CF) energy levels and the fine structure of the orbital ground state as well as the zero-field splitting (ZFS) parameters are investigated for Cr 2+ in the mixed system Rb2MnxCrl_xCl 4. The CF parameters from the earlier superposition model analysis are used as input for a newly developed computer package to diagonalize the orthorhombic CF and spin-orbit Hamiltonian for two cases, namely, the 5D approximation and the 5D-3F~ one. The results show that the spin-triplets (3F,) contributions to the fine structure of the orbital ground state and the ZFS parameters are not negligible, although all 3F~ states lie above the 5D states. The theoretical CF levels for different Cr 2+ concentrations (x) are in good agreement with experimental spectroscopic data. For the axial ZFS parameter b~, the theoretical result is consistent with the experimental magnetic anisotropy data. A change in the sign of the orthorhombic ZFS parameter b~ with Cr 2+ concentration x increasing from x = 0 to x = 0.01 is predicted. This is consistent with the crystal structure data which indicate a 'structural phase transition' with x at low temperatures. EPR studies would help to solve the question of the sign of b~ unambiguously.