As shown earlier, there is a "slow" constituent (<$E gamma>) into oxygen nonstoichiometry in superconducting 123-cuprates doped with rear-earth elements. The aim of this paper is to study possible effect of changing "slow" oxygen content on electrophysical properties of HTSC cuprates. Magnetization of Sm-doped samples YBa1,90Sm0,10Cu3Ox was measured in a vibrating sample magnetometer in scanning magnetic field and temperature. Two series of samples <$E roman {YBa sub 1,90 Sm sub 0,10 Cu sub 3 O sub {6+ delta + gamma}}> were prepared for measurements from the same batch of material: with maxim (<$Egamma sub max~=~0,10>) and minimum (<$Egamma sub min~=~0,00>) values of "slow" oxygen content and corresponding to formulas YBa1,90Sm0,10Cu3O7,07 and YBa1,90Sm0,10Cu3O6,97 respectfully. Both types of samples were obtained from the same batch of sintered material. Samples (I) were brought to equilibrium at <$E720~symbol Р roman C> (lower than Tb1) to maximize the "slow" oxygen content: <$E gamma sub max~=~0,10>. Then they were cooled to <$E400~symbol Р roman C> and kept at this temperature for 1 h to maximize "quick" oxygen content. The final total oxygen content in the samples of this series was established at x (I) = 7,07 (YBa1,90Sm0,10Cu3O7,07. Samples (II) were brought to equilibrium at <$E900~symbol Р roman C> (above Tbb2) to minimize the "slow" oxygen content: <$Egamma sub min~=~0,00> and then they were rapidly (in less then 10 min) cooled to and kept at <$E400~symbol Р roman C> for 1 h. The final total oxygen content in the samples of this series was equal to x (II) = 6,97 (YBa1,90Sm0,10Cu3O6,97. The study of magnetic hysteresis in these samples shows that additional oxidation with respect to "slow" component produces HTSC with higher both the critical temperature Tc and intragrain critical current density Jcg in ceramic specimens. The maximum value of <$Eroman {J sub cg~symbol Ы~3~cdot~06~A "/" cm sup 2}> in untextured ceramic specimens was observed.

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