Antiparallel ruthenium coupling in doped La1.2Sr1.8Mn2−xRuxO7

Abstract

X-ray magnetic circular dichroism measurements in the hard and soft x-ray region have been performed at Mn K and L2,3 edges of the ruthenium (with x=0.05, 0.1 and 0.5) doped Ruddlesden–Popper-phase La1.2Sr1.8Mn2−xRuxO7. In combination with magnetometry, clear evidence of unexpected antiferromagnetic sublattice coupling between manganese and ruthenium was found. A simple coupling model of Mn+3/Mn+4 and Ru+3/Ru+4 ions in the high-spin state is proposed which explains the antiparallel alignment and the technological interesting increase of the Curie temperature.