Magnetic exchange coupling in (Dy,Tb)FeCo magneto-optical recording films

Abstract

The required bias field of a sperimagnetic film is governed by a finite exchange coupling coefficient (λ) mainly determined by the subnetwork coupling. From the study of a series of (Dy,Tb)FeCo films at compensation composition, it is found that λ is mainly determined by the concentration of the rare earth components. Moreover, the exchange integral between rare earth and transition metal subnetworks can be derived from λ so that the number of uncertain parameters for mean field modeling is reduced. Accordingly, the bias field required for magneto-optical recording is mainly proportional to λ that can be obtained quantitatively from either measurement and/or mean field modeling.

Contributions of electron and phonon transport to the thermal conductivity of GdFeCo and TbFeCo amorphous rare-earth transition-metal alloys

“…Note that this is in acceptable agreement with previously reported values for the atomic density of TbFeCo (6:5 Â 10 28 m À3 -Ref. 15) and calculations of atomic density based on the density of the elemental constituents and a rule of mixing ($6 Â 10 28 m À3 ). With our calculated estimates of the heat capacities, we then fit the TDTR thermal model to the experimental data with the only free parameters being the thermal boundary conductance between the Al film and the amorphous RE-TM alloy and the thermal conductivity of the amorphous RE-TM alloy.…”

“…Amorphous RE-TM alloys have received much attention with respect to their application as magneto-optical recording media with GdFeCo and TbFeCo alloys being the most promising candidates. 1,[13][14][15][16] These recording systems utilize the heating effect of a laser beam for storing digital information in a multilayer disk, and the storage and operation of these systems depend immensely on the thermal properties of the disk layers. However, the data for the thermal conductivity of GdFeCo and TbFeCo alloys are relatively nonexistent and only estimates are available at room temperature.…”

Magneto-optical Faraday activity in transparent FeCo-sepiolite/polystyrene nanocomposites

“…The approach of this work is very similar though in this case the purpose is to prepare easy-to-handle optically transparent "magnetic plastics". In the present case, the choice of FeCo as the ferromagnetic material is based on its large magnetic anisotropy and magneto-optical behavior, which make it interesting for different applications such as magneto-optical recording (Hwang et al, 1997;Stavrou et al, 2000) and photonic crystals (Chen et al, 2011).…”