Varying Eu2+ magnetic order by chemical pressure in EuFe2(As1-xPx)(2)

Based on low-field magnetization measurements on a series of single crystals, we present a scheme of the Eu2+ spin alignment in EuFe2(As1-xPx)(2). We explain observations of the Eu2+ ordering previously reported, reconciling different existing phase diagrams. The magnetic moments of the Eu2+ ions are slightly canted, yielding a ferromagnetic contribution along the c direction that becomes stronger with pressure, until superconductivity sets in. The spin-density wave as well as the superconducting phase coexist with an antiferromagnetic interlayer coupling of the canted spins. Reducing the interlayer distance finally leads to a ferromagnetic Eu2+ interlayer coupling and to the suppression of superconductivity. RI Dressel, Martin/D-3244-2012