Temperature dependence of interlayer coupling in Fe/Cr superlattices - FMRstudies

The ferromagnetic resonance in a [Fe(30 Angstrom)/Cr(10 Angstrom)](10), sup erlattice with a relatively large value of biquadratic coupling constant wa s studied in a temperature range from 400 K down to liquid-nitrogen tempera ture. The monocrystalline sample was grown by means of the MBE technique on a MgO [100] substrate. Measurements were performed in magnetic fields up t o 10 kOe at frequencies ranging from 17 to 37 GHz under both transversal an d longitudinal FMR excitations. Resonance spectra with several modes includ ing the acoustic and the optical branches were observed in the whole temper ature range. Temperature dependence of both bilinear and biquadratic coupli ng constants was derived from the experimental spectra. (C) 2001 Elsevier S cience B.V. All rights reserved.