Broadband magnetic and dielectric properties of U-type hexaferrite Sr.sub.4./sub.CoZnFe.sub.36./sub.O.sub.60./sub.

0584974 - FZÚ 2025 RIV NL eng J - Journal Article
Bovtun, Viktor - Kempa, Martin - Repček, Dalibor - Savinov, Maxim - Buršík, Josef - Heczko, Oleg - Drahokoupil, Jan - Kamba, Stanislav
Broadband magnetic and dielectric properties of U-type hexaferrite Sr₄CoZnFe₃₆O₆₀.
Journal of Magnetism and Magnetic Materials. Roč. 589, Jan (2024), č. článku 171533. ISSN 0304-8853. E-ISSN 1873-4766
R&D Projects: GA ČR(CZ) GA21-06802S; GA MŠMT LM2023065
Institutional support: RVO:68378271 ; RVO:61388980
Keywords : hexaferrite * magnetic phase transitions * permeability * permittivity * microwave
OECD category: Condensed matter physics (including formerly solid state physics, supercond.); Inorganic and nuclear chemistry (UACH-T)
Impact factor: 2.7, year: 2022

Ceramics with U-type hexaferrite crystal structure were for the first time prepared and their structural, dielectric, magnetic and magnetoelectric properties were characterized. Broadband dielectric spectra (1 Hz − 1 GHz) showed giant permittivity due to two Maxwell-Wagner dielectric relaxations whose frequencies follow the Arrhenius law. These relaxations are caused by inhomogeneous conductivity in the ceramic grains and their boundaries. Temperature and magnetic field dependences of magnetization revealed a ferrimagnetic phase transition and other two magnetic phase transitions. Very small polarization at 10 K has probably extrinsic origin, so the sample is probably not multiferroic. High-frequency magnetic permeability measured up to 1.8 GHz evidences the Curie-Weiss behavior above Tc2 and Tc3 and two magnetic field-dependent excitations which exhibit anomalies at magnetic phase transitions. We attributed these excitations to the magnetic domain wall dynamics.
Permanent Link: https://hdl.handle.net/11104/0352760