Magnetic anisotropy of ferromagnetic layered manganites

The magnetic anisotropy of the ferromagnetic layered manganites La<InlineEquation ID="Equ1"> <EquationSource Format="TEX">$_{2-2x}{\rm Sr}_{1+2x}{\rm Mn}_2{\rm O}_7$</EquationSource> </InlineEquation> is investigated. For x=0.4, the easy-plane anisotropy comes out predominantly from dipolar interaction but it is partly cancelled out by a significant uniaxial magnetocrystalline anisotropy. This latter one is discussed on the basis of a simple single ion model and compared to existing experimental data in ferromagnetic manganites. Copyright Springer-Verlag Berlin/Heidelberg 2003