Temperature dependence of interlayer coupling in a Fe/Cr/Fe wedge sample. MOKE and MBLS studies

The interlayer coupling in a Fe(100 Angstrom)/Cr(0-22.5 Angstrom)/Fe(100 Angstrom) sample with a wedge-type chromium spacer was investigated as a function of chromium thickness and temperature. Two experimental methods were used for the interlayer coupling determination: the static magnetization curves of the sample were measured by means of the magneto-optical Kerr effect (MOKE) technique in the 77-473K temperature range, and the Mandelstam-Brillouin light scattering (MBLS) experiments were performed to measure the spin-wave spectra of the sample at room temperature. The data obtained via two methods can be well described in the frame of the biquadratic coupling model and are in a good agreement with each other. The bilinear coupling oscillates with the chromium spacer thickness having a period of two monolayers (in agreement with the known experimental results). The biquadratic coupling constant J(2) decays with the increase of the spacer thickness monotonically, showing a 1/t(Cr) behaviour at all temperatures. The bilinear coupling temperature dependence is very weak and could not be distinguished within our experimental accuracy, while the biquadratic coupling demonstrates a relatively strong temperature dependence, which can be considered as linear. (C) 2002 Elsevier Science B.V. All rights reserved.