X-ray diffraction pattern of the La0.8Ag0.2CoO3 cobaltite.
Resistance values of hole-doped LSACO cobaltites, normalized to the resistance at 300 K as a function of temperature at different doping levels. R 300K, Ω: 2.42 (1); 0.0077 (2); 0.0026 (3); 0.00123 (4).
Minimum in the temperature dependence of the normalized resistance of hole-doped cobaltites LSCO and LSACO at the level of substitution of lanthanum with strontium x ≈ 0.35 for B = 0 and B = 0.5 T. R 4.2K, Ω: LSCO – 4.7·10−4; LSACO – 0.0014. Symbols – experiment; solid lines – fitting curves calculated by the formula (1), see text. Dotted curve – the connecting line. On the inset – temperature dependence of resistance of LSACO in B = 0 and B = 0.5 T.
Normalized resistance with a minimum (dots) and fit, calculated by the formula (1) (solid line 1) for the sample LSACO (x = 0.35, y = 0.05). Shown separately are the intrinsic granular contribution (curve 3) and the intergranular contribution (curve 2). Curve 4 is the spin-correlation function for the AFM interaction of granules.
The temperature dependence of resistivity of samples with similar geometrical dimensions of the cobaltites LSCO (x = 0.35, y = 0.05) and LSACO (x = 0.35, y = 0.05) in B = 0 (curves 1 and 3) and applied magnetic field of 10 T (curves 2 and 4).
Temperature dependence of magnetoresistance of cobaltites LSCO (x = 0.35, y = 0) and LSACO (x = 0.35, y = 0.05) in a magnetic field of 10 T.
Basic theoretical fit-parameters, obtained from the analysis of experimental data.
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