Direct observation of the ferrimagnetic coupling of A-site Cu and B-site Fe spins in charge-disproportionated CaCu3Fe4O12

Abstract

The magnetic coupling between Fe and Cu moments in the charge- disproportionated CaCu3Fe4O12 is studied by neutron powder diffraction, x-ray absorption, and magnetic circular dichroism measurements. The magnetic moments of the B-site Fe are coupled antiferromagnetically with those of the A′-site Cu, and the Fe3+ and Fe5+ spins at the B site align ferromagnetically. The orbital contribution of the magnetic moment for Fe is significant and appears to stabilize the ferrimagnetic structure of charge-disproportionated CaCu3Fe4O12. © 2011 American Physical Society.