Biquadratic exchange coupling in sputtered Fe/Cr/Fe(100) sandwich structures

Abstract

We have used magnetoresistance, magneto-optical Kerr effect, ferromagneti resonance (FMR), and Brillouin light scattering to investigate interlayer exchange coupling in Fe(40 Å)/Cr(t)/Fe(40 Å) trilayers. At the right-hand side of the first antiferromagnetic peak (13 Å<t<16 Å), a common feature in both transport and magnetic measurements is the presence of sudden discontinuous jumps as the magnetic field is varied. By treating both transport and magnetic data on equal footing, we demonstrate that all measurements can be described by model calculations which elegantly take into account the same set of phenomenological parameters, characterizing the magnetic anisotropy. Zeeman, and bilinear and biquadratic exchange energies. Temperature-dependent FMR measurements reveal intriguing similarities between the bilinear and biquadratic coupling behaviors. © 1997 American Institute of Physics.