Magneto-Optical Properties of Multilayer Nanostructures with Composite Magnetic Layers near Percolation Threshold

Abstract

Spectra and field dependencies of Transversal Kerr Effect (TKE) for [(Co45Fe45Zr10)46(Al2O3)54(X)/Si (Y)]nmultilayers (ML) with thin layers (X < 2,5 nm; Y < 3,5 nm) have been studied in the energy range 0,5 – 4,0 eV. It was found that TKE field dependencies in the nearest infrared (IR) and visible energy ranges exhibit anomalous behavior. TKE spectra measured in weak (~30 Oe) and strong (~2 kOe) magnetic fields were essentially different. It was shown that magneto-optical response of multilayered structure composite-silicone is the sum of magnetic composite layers and composites formed on interface contributions. And these contributions may have an opposite sign of TKE. Interface magnetic states depend on composite and semiconductor layers’ thicknesses and FM phase concentration in composite layers.

Magneto-Optical Response Amplification In Multi-Layer Nanocomposite-Semiconductor Structures

“…A further increase of the interlayer thickness leads to a weakening of the effect and a reduction of the magnetization curve back to the superparamagnetic type. The spectrum shape changes as well: the effect becomes positive over the entire wavelength range, the spectrum shape becomes similar to the bulk nanocomposite with CoFeB granules in a complex SiO 2 +Si matrix or/and silicides like in [11]. Such behavior of the first ML series can be explained by a fact that a new nanocomposite (CoFeB) in a complex matrix (SiO 2 +Si) is formed on the interface of ferromagnetic granule-silicon, as in the case considered in [11].…”

“…The ML MO response considerably weakens as C is being replaced with Si. The decrease of magneto-optical response could be associated with the higher chemical activity of Si compared with C as well as with the mutual compensation between TKE of the base composite layer and TKE of a new composite formed at the "FM granule-semiconductor" interface with Si, which may have opposite signs [11]. The assumption of mutual compensations is confirmed by positive sign of TKE signal in whole investigated wavelength range from samples with the thickest silicon layers (Fig.4).…”