Influence of the charge ordering and quantum effects in heterovalent substituted hexaferrites on their microwave characteristics

M-type hexagonal ferrites with heterovalent substitutions (Nd3+-Zn2+ and Ti4+) were synthesized. X-Ray diffraction (XRD) powder patterns of Sr(Nd,Zn)xFe12-xO19 and BaFe12-xTixO19 (0.1 ≤ x ≤ 1.0) confirmed the single phase constitution of all investigated samples. High frequency magnetic (permeability), electrical (permittivity), and resonant properties were analyzed. Unexpected behavior in the permittivity and permeability as a function of frequency was observed. Appearance of two peaks for samples with x = 0.1 and 0.9 indicated mixed oxidation state for the Fe ions. Behavior for Sr(Nd,Zn)xFe12-xO19 (0.3 ≤ x ≤ 0.7) confirms the occurrence of the anomalous quantum effect, namely charge disproportionation. The permeability behavior of Ti-substituted samples with a double Fe oxidation state was theoretically discussed in terms of spin states crossover. The behavior of reflection losses for Sr(Nd,Zn)xFe12-xO19 and BaFe12-xTixO19 (0.1 ≤ x ≤ 1.0) samples was discussed in terms of the modalities of charge ordering in heterovalent substituted M-type hexaferrites.

Citation

Trukhanov, A. V., Almessiere, M. A., Baykal, A., Trukhanov, S. V., Slimani, Y., Vinnik, D. A., … Zdorovets, M. (2019). Influence of the charge ordering and quantum effects in heterovalent substituted hexaferrites on their microwave characteristics. Journal of Alloys and Compounds, 788, 1193–1202. doi:10.1016/j.jallcom.2019.02.303

Sponsors

The work was supported by Act 211 Government of the Russian Federation, contract № 02.A03.21.0011. And also it was performed with partial financial supports from the Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of NUST « MISiS» (grants No. П02-2017-2-4, No. К3-2018-026, No. К4-2017-041) and SUSU (grant No. 4.1346.2017/4.6). Financial supports from Institute for Research & Medical Consultations (IRMC) of Imam Abdulrahman Bin Faisal University (IAU – Saudi Arabia) are greatly acknowledged [Grant No. 2018-IRMC-S-1]. The Core Labs of King Abdullah University of Science and Technology (KAUST) are greatly acknowledged for their technical assistance. Electromagnetic measurements were performed at the expense of a grant from the Russian Science Foundation (project No. 18-79-00154).