Superexchange interaction and spin transfer to a ligand in K2CuCl4∙2H2O-type crystals

Abstract

The superexchange interaction between magnetic copper ions in the paramagnetic state of K2CuCl4∙2H2O-type crystals has been investigated in terms of the molecular-orbital method. A formalism for the exchange constant, proportional to the square of the spin transfer to the nonmagnetic ligand that is involved in the superexchange path, is obtained. The temperature-dependent exchange constant resulting from the temperature-dependent spin transfer to H is compared with that determined by Cu2+ electron spin resonance and with the thermal average of the exchange interaction. A reasonable agreement is observed.