INFLUENCE OF IONIC SUBSTITUTION ON THE MAGNETIC-BEHAVIOR OF Y2CU2O5

The influence of the substitution of Cu or O by various elements on th e magnetic properties of Y2Cu2O5 has been studied. The substitution of Cu by metal ions with unpaired d electrons (M = Co2+, Ni2+) makes the superexchange in Cu2O8 chains stronger, but the substitution by those metal ions without unpaired electrons (M = Zn2+, Mg2+) makes the supe rexchange weaker. The substitution of O by S also makes the superexcha nge weaker. Magnetic properties of Y2Cu2-xMxO5 and Y2Cu2O5-ySy were st udied between 77 K and room temperature. Samples were characterized by X-ray diffraction (XRD), electron paramagnetic resonance (EPR) and th ermal gravimetry (TG).