Ferromagnetic-antiferromagnetic transition in „La-R...4Ba2Cu2O10
نویسنده
چکیده
Cuprate La-R 4Ba2Cu2O10 shows ferromagnetic to antiferromagnetic phase transition by replacing La ions with rare earth R=Nd, Sm, Eu, and Gd ions at low temperature. We propose that the transition is caused by a competition between antiferromagnetic superexchange interaction of Cu spins via La ions and ferromagnetic superexchange interaction due to Hund’s rule coupling of spins of holes on oxygen ions. It is shown that the ferromagnetic interaction becomes antiferromagnetic with increasing overlap between the wave functions of oxygen and La R ions.
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