High-resolution neutron powder diffraction experiments and magnetization measurements were performed for a series of the electron-doped infinite-layer high-temperature superconductors Sr 1− x R x CuO 2 (R=La, Pr; 0.07⩽ x⩽0.15). Zero-field-cooled magnetization measurements performed for the powder Sr 0.9Pr 0.1CuO 2 sample under hydrostatic pressure up to 0.5 GPa at a magnetic field of 0.005 T revealed a downward shift of the onset temperature T c onset of the diamagnetic response described by the pressure derivative d T c onset/d p=−(0.75±0.30) K/GPa. By measuring the reversible superconducting magnetization for the powder aligned Sr 0.9Pr 0.1CuO 2 sample at high fields 1⩽ μ 0 H⩽5 T, we found that the 3D-lowest-Landau-level approximation is a good description of fluctuation magnetization, if one takes into the curvature of the critical line B c2( T)∝| T− T c| 4/3.