Coupled electrical and magnetic properties in (La,Sr)FeO3−δ

Abstract

Articles you may be interested inThe effect of Cu-doping on the magnetic and transport properties of La 0.7 Sr 0.3 MnO 3

Coupling Between Magnetic Exchange and Charge Activation in Cu‐Doped LaFeO3

“…11 For x = 0.01, 0.05, E a,n values are in a good agreement with these calculated from E a,r ÀE a,m , where E a,r is the activation energy for electrical conductivity. 3 Therefore, at low-temperature, Cu is assumed to be 3+ in LaFeO 3 and is reduced to 2+ at higher temperature. 6 at T > 500°C, at which the carrier density is independent on the temperature.…”

“…Electrostatic energy within the lattice allows electron addition to these degenerate d orbitals, leading to formation of Fe 3+ /Fe 2+ (n type) and Fe 4+ /Fe 3+ (p type) redox couples, 12 both of which were experimentally observed previously. 3 Therefore, at low-temperature, Cu is assumed to be 3+ in LaFeO 3 and is reduced to 2+ at higher temperature. The lower ionization energy of the Cu 3+ /Cu 2+ (16.5 eV) redox couple compared with Fe 4+ / Fe 3+ (24.1 eV) further suggests a Cu 3+ oxidation state in LaFeO 3 rather than Cu 2+ , which leads to carrier formation that participate in the hopping mechanism.…”

“…Our previous studies showed that oxygen vacancies were the origin of coupled electrical and magnetic properties in La 1Àx Sr x FeO 3Àd , 2-5 a series of compounds of great interest in oxygen gas separation and solid oxide fuel cells. The parent compound, LaFeO 3 , is an antiferromagnetic insulator with distorted orthorhombic structure. Its magnetic properties are driven by antiferromagnetic superexchange interactions.…”

“…Neutron diffraction patterns of LaFe 0.9 Cu 0.1 O 3 at different temperatures. The first one (label 1) is a purely magnetic peak, and the other three(2,3,4) are nuclear peaks.…”

Evolution of Electronic Spectrum and Magnetic Properties of the High‐Temperature Cubic Phase La1−xSrxFeO3−δ in Coherent Potential Approximation

“…However, when oxygen vacancies are being filled at δ → 0, the energy gap is closing and metallic‐like properties appear . According to low‐temperature neutron diffraction data, the magnetic moment of Fe 3+ ions in LaFeO 3 varies from 3.8 to 4.6 µ B . The magnetic moment in the composition х = 0.4 decreases slightly to 3.7–3.8 µ B being almost independent on temperature at 290–1773 K and δ = 0.2–0.3 .…”