METAMAGNETISM OF CUPRATES R2CU2O5

We have measured the magnetization in static magnetic fields up to 60 kOe and pulse magnetic fields up to 250 kOe and the magnetic susceptibility in weak ac fields for polycrystals of cuprates R2Cu2O5 (R = Tb-Lu, Y, Sc, In), and for monocrystal of Er2Cu2O5, compounds which are related to high-Tc superconductors RBa2Cu3O7-δ. These compounds are antiferromagnets most of them (except Tb2Cu2O5 and perhaps Tm2Cu2O5) shows metamagnetic behavior. Most of the cuprates exhibits one metamagnetic transition, cuprates with Y and Sc exhibit two transitions, and Yb2Cu2O5 has four transitions. The experimental data are discussed qualitatively within the conception of the low-dimensional character of magnetic ordering of a copper subsystem in R2Cu2O5. © 1990.