Strong ferromagnetic coupling in the K2NiF4-structured oxide La0.8Sr1.2Mn0.6Rh0.4O4

Abstract

Substitution of diamagnetic Rh^III into the antiferromagnet LaSrMnO₄ produces the first example of a K₂NiF₄ (n=1 Ruddlesden–Popper) oxide with strong ferromagnetic interactions—in 50 kG at 5 K the magnetisation of La_0.8Sr_1.2Mn_0.6Rh_0.4O₄ is close to saturation at 2.50 µ_B per Mn cation; the bulk magnetisation stems from the alignment by the magnetic field of ferromagnetic (Mn/Rh)O₂ sheets which are not magnetically ordered along [001] in zero applied field.