Preparation and Magnetic Properties of LaMnO₃₊δ (0≤ δ ≤0.154)

The structural, electrical, and magnetic properties of ceramic perovskite manganites LaMnO₃₊δ (δ = 0-0.154) are investigated. It is found that, in a weak magnetic field ( B = 2 G), the LaMnO₃₊δ manganite with δ= 0.065 at temperatures below the Curie temperature Tс of the paramagnet -ferromagnet phase transition has a mixed (spin glass + ferromagnet) phase. In LaMnO₃₊δ manganites with the parameter δ = 0.100-0.154, this phase transforms into a frustrated ferromagnetic phase. A similar transformation was observed previously in La₁₋ₓ CaₓMnO₃ сompounds at calcium contents in the range 0 ≤ x ≤ 0.3yesBelgorod State Universit

Hopping conductivity of Ni-doped p-CdSb in strong magnetic fields

In this work detailed investigation of the hopping conductivity in p-CdSb:Ni in strong magnetic field is reported to complete the picture of hopping charge transfer in this materialyesBelgorod State Universit

Unconventional critical behavior of magnetic susceptibility as a consequence of phase separation and cluster formation in La₀.₇Ca₀.₃MnO₃ thin films

Nonuniversal critical behavior of the dc magnetic susceptibility is observed near the paramagnetic to ferromagnetic transition in La₀.₇Ca₀.₃MnO₃ film samplesyesBelgorod State Universit

Variable-range hopping conductivity in La₁₋xCaxMn₁₋yFeyO₃: evidence of a complex gap in density of states near the Fermi level

The resistivity, ρ, of ceramic La₁₋xCaxMn₁₋yFeyO₃ with x = 0.3 and y = 0.0–0.09 is found to obey, between a temperature Tv ≈ 310–330 K and the ferromagnetic-to-paramagnetic transition temperature, Tc = 259–119 K (decreasing with y), the Shklovskii–Efros-type variable-range hopping conductivity law, ρ(T) = ρ₀(T) exp[(T₀/T)¹/₂]. This behaviour is governed by generation of a soft Coulomb gap Δ ≈ 0.42 eV in the density of localized states and a rigid gap δ(T) ≈ δ(Tv)(T/Tv)1/2 with δ(Tv) ≈ 0.16, 0.13 and 0.12 eV at y = 0.03, 0.07 and 0.09, respectively. Deviations from the square root dependence of δ(T), decreasing when y is increased, are observed as T → TC. The prefactor of the resistivity follows the law ρ₀ (T) ~ Tm, where m changes from 9/2 at y = 0 to 5/2 in the investigated samples with y = 0.03, 0.07 and 0.09, which is connected to introduction of an additional fluctuating short-range potential by doping with FeyesBelgorod State Universit

The Hall effect in Ni-doped p-CdSb in a strong magnetic field

The Hall effect in single crystals of the group II–V semiconductor p-CdSb doped with 2 at% of Ni is investigated between T = 1.5 and 300 K in pulsed magnetic fields up to B = 25 T. The Hall resistivity, ρH, exhibits a nonlinear dependence on B, which is strongly pronounced below ~10 K but is still observed even up to 300 KyesBelgorod State Universit

Variable-range hopping conductivity of La₁₋xSrxMn₁₋yFeyO₃

The temperature dependence of the resistivity,ρ, of ceramic of La₁₋xSrxMn₁₋yFeyO₃ (LSMFO) samples with x=0.3 and y=0.03, 0.15, 0.20 and 0.25 (or simply #03, #15, #20 and #25, respectively) is investigated between temperaturesT∼5 and 310 K in magnetic fields B up to 8 TyesBelgorod State Universit

Magnetization and Shubnikov-de Haas effect in diluted magnetic semiconductors (Cd₁₋x₋yZnxMny)₃As₂

Presents the results of the Shubnikov-de Haas (SdH) effect and magnetization of single crystals of (Cd1-x-yZnxMny)3As2 magnetic semiconductors. Analysis of SdH oscillations; Exchange constant in the conduction band and spin-dependent part of the Dingle temperatureyesBelgorod State Universit

Electrical conductivity and magnetic properties of La1-xCaxMn1-yFeyO3 Ceramic Samples (x= 0.67, y= 0, 0.05)

The temperature dependence of the electrical resistivity in the range of the charge-ordered phase conforms to the variable-range hopping model. The behavior of the electrical resistivity is governed by the complex structure of the density of localized states near the Fermi levelyesBelgorod State Universit

Magnetic properties of the new diluted magnetic semiconductor Zn₁₋ₓMnₓAs₂: evidence of MnAs clusters

The preparation and magnetic properties of the diluted magnetic semiconductor Zn₁₋ₓMnₓAs₂, opening a novel group of II–V₂ compounds alloyed with transition metal elements, are reported for the first timeyesBelgorod State Universit

Critical behavior of magnetoresistance near the metal-insulator transition of La₀₇Ca₀₃MnO₃

The resistivity, ρ(T), of thin film and bulk samples of La₀₇Ca₀₃MnO₃ is investigated in magnetic fields between 0-10 T and temperatures between 10-340 K. Metallic resistivity, ρlt(T)=ρr+ρ2T2+ρ4.5T4.5, is observed well below the metal–insulator transition (MIT) temperature TMI. For T>TMI, the resistivity is governed by the Shklovskii-Efros variable-range hopping mechanism, giving View the MathML sourceyesBelgorod State Universit