Competing magnetic interactions in (Dy_0.375Y_0.625)₂Cu₂O₅ solid solution studied by EPR

Abstract

structure has been found in the EPR spectrum and the values of appropriate exchange constants connected with a hierarchy of exchange interactions has been calculated. At about 40 K a dimensional crossover from 2D to 3D behaviour has been observed in the temperature dependence of the product of the EPR integrated intensity and temperature. At high temperatures (T > 200 K) the EPR spectrum is suggestive of the presence of defect centres consisting of antferromagnetically coupled copper spins, forming dimers with the S = 0 ground state.