Sub-lattice of Jahn-Teller centers in hexaferrite crystal

• Published in: Scientific reports Vol. 10; no. 1; p. 7076
• Main Authors: Gudkov, V. V., Sarychev, M. N., Zherlitsyn, S., Zhevstovskikh, I. V., Averkiev, N. S., Vinnik, D. A., Gudkova, S. A., Niewa, R., Dressel, M., Alyabyeva, L. N., Gorshunov, B. P., Bersuker, I. B.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 27.04.2020; Nature Publishing Group
• Subjects: 639/766/119/996; 639/766/25/3927; 639/766/400/561; Adiabatic; Approximation; Barium; Chemical elements; Chemistry; Humanities and Social Sciences; Ions; Iron; Magnetic fields; multidisciplinary; Phase transitions; Physics; Potential energy; Quantum theory; Science; Science (multidisciplinary); Symmetry; Ultrasound
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-020-63915-7

A novel type of sub-lattice of the Jahn-Teller (JT) centers was arranged in Ti-doped barium hexaferrite BaFe 12 O 19 . In the un-doped crystal all iron ions, sitting in five different crystallographic positions, are Fe 3+ in the high-spin configuration (S = 5/2) and have a non-degenerate ground state. We show that the electron-donor Ti substitution converts the ions to Fe 2+ predominantly in tetrahedral coordination, resulting in doubly-degenerate states subject to the E ⊗ e problem of the JT effect. The arranged JT complexes, Fe 2+ O 4 , their adiabatic potential energy, non-linear and quantum dynamics, have been studied by means of ultrasound and terahertz-infrared spectroscopies. The JT complexes are sensitive to external stress and applied magnetic field. For that reason, the properties of the doped crystal can be controlled by the amount and state of the JT complexes.