Artificial magnetic domains by interlayer coupling in an in-plane/perpendicular-to-plane magnetic bilayer system

Artificial magnetic domains are induced into a soft-magnetic in-plane <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:msub><a:mi>Co</a:mi><a:mn>60</a:mn></a:msub><a:msub><a:mi>Fe</a:mi><a:mn>20</a:mn></a:msub><a:msub><a:mi mathvariant="normal">B</a:mi><a:mn>19</a:mn></a:msub><a:msub><a:mi>Si</a:mi><a:mn>1</a:mn></a:msub></a:mrow></a:math> (CoFeBSi) alloy by interlayer coupling to a perpendicular-to-plane FePt underlayer. We present images documenting the thickness dependence of the size of magnetic domains inside the CoFeBSi ferromagnetic layer. The magnetic domain walls in FePt induce a continuous progression of domain walls into the CoFeBSi at the vicinity of the interface to FePt. With femtosecond laser pulses, the recurrent domain pattern in CoFeBSi has been investigated after reversing the magnetization and we observe a reorganization into the thickness-dependent multidomain state inside the CoFeBSi with strong domain-wall pinning at the interface.