ISSN:
1090-6509
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract A comparative study of the longitudinal ρ xx and transverse ρ xy resistivities and magnetic susceptibility χ ac of La0.8Sr0.2MnO3 single crystals and ceramic samples has been conducted in a wide range of temperatures T=1.7–370 K and magnetic fields, H=0–13.6 T. It turned out that the relation ρ xy ∼ρ xx , which is expected to hold in the case of carrier scattering by magnetic fluctuations, applies to the single crystals. In polycrystals, an additional H-dependent contribution to the resistivity tentatively attributed to plane (near grain boundaries) and bulk “defects” of the magnetic sublattice has been detected. The scattering of carriers by these defects does not make a notable contribution to the anomalous Hall effect and magnetic susceptibility χ ac. As a result, the curve of ρ xy versus ρ xx seems to be steeper than a linear dependence. Under the assumption that the materials under investigation are metals with constant carrier concentrations, the conductivity σ=1/ρ xx due to the critical magnetic scattering calculated in the molecular field approximation reproduces the main features of experimental data, namely, the drop in the amplitude and shift of the resistivity peak near the Curie point with increasing magnetic field H and also a relatively slow change in the derivative dσ/dH with increasing temperature in the region T⩽T C . The large hole concentration of about two per unit cell derived from Hall measurements indicates that carriers of opposite signs can coexist in these materials.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1134/1.558992
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