14 research outputs found
Hall effect in the new diluted magnetic semiconductor p-CdSb:Ni
The anomalous contribution to the Hall effect is attributable to presence of magnetic Ni1–xSbx nanoclusters, which have been found previously from investigation of magnetic properties of p-CdSb:NiyesBelgorod State Universit
Mechanisms of hopping conductivity in weakly doped La₁₋ₓВaₓMnO₃
The localization radius of the charge carriers, a, has different constant values within the temperature intervals where δ(T) ~ T½. With further decrease of T, a increases according to the law expected for small lattice polaronsyesBelgorod State Universit
Magnetoresistance and Anomalous Hall Effect of InSb Doped with Mn
Transport properties of polycrystalline (In, Mn)Sb samples are investigated. Behavior of the temperature and magnetic field dependencies of the resistivity, anomalous Hall coefficient and magnetoresistivity at low temperatures points out the influence of Mn complexes, Mn ions and nano- and microsizes MnSb precipitates on charge transport.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3361
Mechanisms of charge transfer and electronic properties of Cu2ZnGeS4 from investigations of the high field magnetotransport
Recent development of the thin film solar cells, based on quaternary compounds, has been focused on the Ge contain compounds and their solid solutions. However, for effective utilization of Cu2ZnGeS4, deeper investigations of its transport properties are required. In the present manuscript, we investigate resistivity, amp; 961; T , magnetoresistance and Hall effect in p type Cu2ZnGeS4 single crystals in pulsed magnetic fields up to 20 T. The dependence of amp; 961; T in zero magnetic field is described by the Mott type of the variable range hopping VRH charge transfer mechanism within a broad temperature interval of 100 200 K. Magnetoresistance contains the positive and negative components, which are interpreted by the common reasons of doped semiconductors. On the other hand, a joint analysis of the resistivity and magnetoresistance data has yielded series of important electronic parameters and permitted specification of the Cu2ZnGeS4 conductivity mechanisms outside the temperature intervals of the Mott VRH conduction. The Hall coefficient is negative, exhibiting an exponential dependence on temperature, which is quite close to that of amp; 961; T . This is typical of the Hall effect in the domain of the VRH charge transfer
Hall effect in the new diluted magnetic semiconductor p-CdSb:Ni
yesThe anomalous contribution to the Hall effect is attributable to presence of magnetic Ni1–xSbx nanoclusters, which have been found previously from investigation of magnetic properties of p-CdSb:NiBelgorod State Universit
Mechanisms of hopping conductivity in weakly doped La₁₋ₓВaₓMnO₃
yesThe localization radius of the charge carriers, a, has different constant values within the temperature intervals where δ(T) ~ T½. With further decrease of T, a increases according to the law expected for small lattice polaronsBelgorod State Universit
Magnetotransport of indium antimonide doped with manganese
Magnetotransport, including the magnetoresistance (MR) and the Hall effect, isinvestigated in polycrystalline In1-xMnxSb samples with x = 0.02 – 0.06, containing nanosize MnSb precipitates. The relative MR, Δρ/ρ, is positive within the whole range of B= 0 – 10 T and T ~ 20 – 300 K. The Hall resistivity, ρH, exhibits a nonlinear dependence on B up to the room temperature.MR is interpreted with the two-band model, suggesting two types of holes with different concentration and mobility. In addition, analysis of ρH (B, T) is performed by taking into account both the normal and the anomalous contributions. The latter is attributable to the effect of MnSb nanoprecipitates, having the ferromagnetic Curie temperature well above 300 K
Magnetotransport of indium antimonide doped with manganese
Magnetotransport, including the magnetoresistance (MR) and the Hall effect, isinvestigated in polycrystalline In1-xMnxSb samples with x = 0.02 – 0.06, containing nanosize MnSb precipitates. The relative MR, Δρ/ρ, is positive within the whole range of B= 0 – 10 T and T ~ 20 – 300 K. The Hall resistivity, ρH, exhibits a nonlinear dependence on B up to the room temperature.MR is interpreted with the two-band model, suggesting two types of holes with different concentration and mobility. In addition, analysis of ρH (B, T) is performed by taking into account both the normal and the anomalous contributions. The latter is attributable to the effect of MnSb nanoprecipitates, having the ferromagnetic Curie temperature well above 300 K
High field hopping magnetotransport in kesterites
Transport properties of the kesterite like single crystals of Cu2ZnSnS4, Cu2ZnSnxGe1 amp; 8722;xSe4 and Cu2ZnGeS4 are investigated in pulsed magnetic fields up to B amp; 8239; amp; 8239;20 amp; 8239;T. The Mott variable range hopping VRH conduction is established by investigations of the resistivity, amp; 961; T , in all the materials mentioned above within broad temperature intervals of amp; 916;Tv4 amp; 8239; amp; 8764; amp; 8239;50 150 amp; 8239;K, 50 250 amp; 8239;K and 100 200 amp; 8239;K, respectively. In addition, the Shklovskii Efros VRH conductivity below Tv2 amp; 8239; amp; 8764; amp; 8239;3 4 amp; 8239;K, the nearest neighbour hopping NNH charge transfer between T amp; 8239; amp; 8764; amp; 8239;250 320 amp; 8239;K and the conductivity by activation of holes on the mobility threshold at temperatures outside amp; 916;Tv4, respectively, are observed in these materials. In Cu2ZnSnS4, magnetoresistance MR contains only a positive contribution, connected mainly to a shrinkage of impurity wave functions by the magnetic field. At the same time, a negative contribution to MR, attributable to interference effects in VRH, is observed in Cu2ZnSnxGe1 amp; 8722;xSe4 and, especially, in Cu2ZnGeS4. The joint analysis of the MR and amp; 961; T data has yielded important electronic parameters of the materials. This includes widths of the acceptor band W and of the Coulomb gap amp; 916;, the NNH activation energy En, the localization radius a, the acceptor concentration NA and the density of the localized states at the Fermi level, g amp; 956; . A dramatic increase of a in Cu2ZnSnS4 with decreasing T is observed, whereas in Cu2ZnSnxGe1 amp; 8722;xSe4 all the parameter W, En, g amp; 956; , a and NA are non monotonic functions of x. Finally, in Cu2ZnGeS4 the Hall coefficient RH T is negative despite of the p type conduction , exhibiting the dependence close to that of amp; 961; T in the Mott VRH interva