Exchange springs in antiferromagnetically coupledDyFe2−YFe2superlattices

Abstract

Molecular beam epitaxy methods have been used to grow single-crystal Laves phase ${\mathrm{DyFe}}_{2}{\ensuremath{-}\mathrm{Y}\mathrm{F}\mathrm{e}}_{2}$ superlattice samples with a (110) growth direction. In this paper, magnetization curves for the multilayer samples $[w{\mathrm{DyFe}}_{2}/w{\mathrm{YFe}}_{2}]\ifmmode\times\else\texttimes\fi{}40,$ with $w=50,$ 75, 100, 150, and 300 \AA{}, are presented and discussed. Below ${T}_{C},$ the magnetic moments of the ${\mathrm{DyFe}}_{2}$ layers are coupled antiferromagnetically to those of the ${\mathrm{YFe}}_{2}$ layers. However, in applied fields, it is possible to generate magnetic exchange springs in the ${\mathrm{YFe}}_{2}$ layers, with well-defined bending (onset) fields ${B}_{B}.$ In particular, it is demonstrated, both experimentally and theoretically, that the bending field ${B}_{B}$ is closely proportional to ${1/w}^{2},$ where w is the thickness of the magnetically soft ${\mathrm{YFe}}_{2}$ layer.