Magnetic linear dichroism of infrared light in ferromagnetic alloy films

Correlation between the Magnetoresistance, IR Magnetoreflectance, and Spin-Dependent Characteristics of Multilayer Magnetic Films

“…Thus, the competition between the intraband and interband contributions leads to a change of sign of MRE as a function of wavelength. This experimental fact contradicts to the predictions of the Drude model [6][7][8][9][10], where the intraband contribution into the conductivity is considered only. Due to such contribution the MRE curve always keeps the same sign.…”

“…We have simulated the MRE of [CoFe(2 nm)/Cu(1.2 nm)] 10 multilayers using the frequency-and spin-dependent conductivity for FM film. Conductivity σ(ω) of the FM layer is a sum of the Drude contributions from majority-and minority-spin electrons [7,8,14]:…”

“…For fitting experimental results the following parameters were chosen according to literature data [8,12,14]: τ f = 1.25 × 10 −14 s closed to the relaxation time of pure Co, α 0 = 3 the spin-asymmetry parameter, τ n = τ Cu = 2.5 × 10 −14 s the spin-independent scattering time in the nonmagnetic layer, Cu. In the external magnetic field the spin-dependent relaxation time changes as a τ…”

“…MRE is an even MO effect, namely, it is linear with magnetization squared, like GMR. Moreover, the MRE is sufficiently larger in the IR region than the corresponding MO values [6][7][8]. Infrared transmission or reflection spectroscopy can provide a direct tool for probing the spin-dependent conductivity in GMR and TMR samples [6][7][8][9][10][11].…”

“…This interest in MRE was motivated by three aspects: (i) its importance as an experimental noncontact (in situ) magnetoresistance tool, (ii) its being a means of measuring the spin-dependent characteristics of ferromagnetic (FM) materials, and (iii) its application in magnetooptical crystal. The main advantages of the MRE 2 Physics Research International over other techniques are following: (i) the surface sensitivity with typical information depth of ∼10-30 nm; (ii) a time resolution can be down to the subpicosecond regime [6,8]; (iii) a reasonable spatial resolution tends to ∼1-10 μm [6,11]; (iv) using robust and inexpensive experimental setups.…”