Magnetic Properties of Spin-Ladder Compound Sr₁₄(Cu_1-yFe_y)₂₄O₄₁

Magnetic properties of spin-ladder compounds Sr14(Cu1-yFey)24O41 (0 ≤ y ≤ 0.05) are investigated in the temperature range from 10 to 300 K. The result reveals that all the samples exhibit magnetic crossover behavior in the paramagnetic range, and Fe3+ doping can efficiently increase the susceptibility due to the large moment of Fe3+. Both the observations are consistent with our previous investigation on transport behaviors, indicating the strong correlation between the magnetism and transport behaviors. The spin gap is evidenced in all the samples, and strengthens as Fe3+ doping level increases, which can be associated with the antiferromagnetic interaction between Fe3+ and Cu cations.