Anomalous frequency behavior of temperature dependent impedance spectra of the LuFe2O4 multiferroic

Abstract

We have measured temperature dependent impedance spectra of LuFe2O4 multiferroic polycrystalline samples in the temperature range of 100–400 K, in a wide frequency range of measuring AC voltage: from 20 Hz to 120 MHz. In spectra measured at 30–70 MHz and at 200–260 К, we observed anomalous positive temperature coefficient of resistance. We explain the anomaly on the basis of the generalized barrier model.

Epitaxial Growth of Orthorhombic GaFeO3 Thin Films on SrTiO3 (111) Substrates by Simple Sol-Gel Method

“…With the coupling of these two properties, these materials show interesting physics such as ferroelectric properties that can be changed by magnetic fields and ferromagnetic properties that can be controlled by electric field [1,2,3,4]. Multiferroic materials can be applied in the development of new devices like sensors [5,6,7], transducers [8,9], second harmonic generation [10] and information storage [11,12,13]. However, most of multiferroic materials exhibit spontaneous polarization and magnetization only at low temperature [14,15].…”

Negative dynamic dielectric permittivity of a ceramic multiferroic LuFe-=SUB=-2-=/SUB=-O-=SUB=-4-=/SUB=- with oxygen nonstoichiometry under the combined influence of temperature and electric field

“…Such materials include the multiferroic compound LuFe 2 O 4 . Numerous experimental data indicate that at a temperature of ∼ 340 K, charge ordering (CO) appears in these compounds, and at T ≈ 240 Kmagnetic ordering (appearance of magnetization due to ordering magnetic moments of iron cations in the compound) [1][2][3][4][5][6]. The LuFe 2 O 4 compound attracts the attention of researchers due to an unusual mechanism for the occurrence of electric polarization due to electron correlation processes and geometric frustration of charges (Fe 2+ /Fe 3+ ) in the temperature range between 350 and 500 K [1].…”

Отрицательная динамическая диэлектрическая проницаемость керамического мультиферроика LuFe-=SUB=-2-=/SUB=-O-=SUB=-4-=/SUB=- с кислородной нестехиометрией при совместном воздействии температуры и электрического поля

“…К числу таких материалов относится мультиферроидное соединение LuFe 2 O 4 . Многочисленные экспериментальные данные свидетельствуют о том, что при температуре ∼ 340 K в данных соединениях возникает зарядовое упорядочение (ЗУ), а при T ≈ 240 K -магнитное упорядочение (возникновение намагниченности вследствие упорядочения магнитных моментов катионов железа в соединении) [1][2][3][4][5][6]. Соединение LuFe 2 O 4 привлекает внимание исследователей из-за необычного механизма возникновения электрической поляризации, обусловленного процессами электронной корреляции и геометрической фрустрацией зарядов (Fe 2+ /Fe 3+ ) в области температур между 350 и 500 K [1].…”