Polarized-neutron-reflectivity confirmation of 90° magnetic structure in Fe/Cr(001) superlattices

Polarized-neutron reflectivity together with magnetization and magnetotransport measurements on a (001)-oriented [Fe(14 Å)/Cr(74 Å)${]}_{20}$ superlattice confirms the existence of 90° alignment of adjacent Fe layers due to biquadratic interlayer coupling. Each Fe layer is in a single domain state and the magnetic structure is coherent throughout the layered stack. The biquadratic coupling, however, is suppressed below the Cr Néel temperature (${\mathit{T}}_{\mathit{N}}$=187 K) as the Fe layers uncouple. But by field cooling through ${\mathit{T}}_{\mathit{N}}$ it is possible to retain a metastable biquadratic arrangement. © 1996 The American Physical Society.