Structural and magnetic properties of the layered perovskite system Sr2−xPrxCoO4 (x = 0.7, 0.9, 1.1)

Abstract

We report the detailed structural and temperature dependent magnetic properties of well characterized, polycrystalline samples of Sr2−xPrxCoO4 (x = 0.7, 0.9, 1.1), in the temperature range 5 K–300 K. In Sr2−xPrxCoO4 (0.7 ≤x≤ 1.1), short range or long range ferromagnetic (FM) order appears below TC~ 150 K. In general the low temperature magnetic state is a mixture of FM, paramagnetic (PM) and antiferromagnetic (AFM) matrices. The spin glass phase (SG) is observed in Sr1.1Pr0.9CoO4 below Tf = 15 K due to comparable strengths of FM and AFM interactions. With increasing x, the Jahn-Teller distortion weakens the FM interaction and AFM interaction starts dominating. Isothermal remanent magnetization (IRM) as a function of time (t) shows that the relaxation mechanism is associated with the interfaces between different types of magnetic matrices.