Papers by Author: L.N. Romashev

Abstract: The magnetooptical and optical properties, and giant magnetoresistance (GMR) of MBE-grown Fe(tx, Å)/Cr10 Å (tx=0.3-30 Å) superlattices and nanostructured multilayers are studied. The data obtained are used for characterization of magnetic clusters in structures with ultrathin Fe layers (tFe<6.6 Å) and for estimation of interfacial electron scattering parameters in GMR superlattices.

Abstract: We investigated the structure, magnetic and magnetoresistive properties of antiferromagnetically coupled [Fe(85Å)/Cr(tCr)]12 superlattices with the Cr layers thickness tCr = 12.4 and 13.6 Å, grown simultaneously on (100)MgO and (211)MgO substrates. It is shown that the (211)MgO substrate is appropriate for the growth of (210)Fe/Cr multilayers with a strong uniaxial in-plane anisotropy. The stepwise behavior of magnetization and magnetoresistance is revealed in the case when the magnetic field is applied along the easy axis in a film plane of (211)MgO/[(210)Fe/Cr]12 superlattices. The steps on M(H) and ΔR(H)/R dependences are caused by the flip of the magnetic moments of individual Fe layers. The qualitative information about the sequence of spin-flip transitions is extracted from the comparative analysis of magnetization and magnetoresistance data.

Abstract: The magnetic and magnetoresistive properties of nanostructured Fe/Cr multilayers with ultra-thin Fe layers (the nominal Fe thickness tFe is down to 0.3 Å) have been investigated at low temperatures (down to 2 K) in magnetic fields up to 90 kOe. Nanostructures were MBE grown in ultrahigh vacuum on single crystal MgO substrates. It is shown that Fe layers in nanostructures with tFe < 2 Å are not continuous but consist of separate ferromagnetic clusters. Such cluster-layered nanostructures exhibit superparamagnetic properties and the Kondo-like behavior of resistivity.