The Analysis of the Magnetorefractive Effect in La 0.7Ca0.3Mno3: Thin Films and Single Crystals

Abstract

Recently, it has been shown that the magnetorefractive effect in reflection and transmission modes in La0.7Ca0.3MnO3 manganite thin films and single crystals can reach several percents for single crystals and up to 20-40% for thin films in the middle infrared spectral range near the Curie temperature. In the present paper, to explain these data we used the effective medium approach and supposed that La 0.7Ca 0.3MnO3 manganites consist of low and high resistivity phases with volume fractions depending on an applied magnetic field. It is shown that the magnetorefractive effect spectra strongly depend on magnetoresistance and optical properties of manganites in the infrared range.

Giant magnetotransmission and magnetoreflection in ferromagnetic materials

“…It corresponds to the theory of magnetorefractive (MRE) effect (intrinsic MRE [49]) developed and applied for manganites [27,50]. In this theory the following relations were derived …”

“…5) indicates that the expressions (1) and (2) are applicable only to optimally doped compounds [43]. In other -more usual -cases the effective medium consisting of regions with different conductivities should be considered [50]. Unfortunately, the effective medium approach or the intrinsic MRE theory provides no more than qualitative agreement with experiment (Fig.…”

“…Calculated spectra of magnetoreflection ΔR/R and magnetotransmission Δt/t for La 0.7 Са 0.3 MnO 3 film (d ¼ 300 nm) at different volume fraction of the conductivity phase y in a magnetic field of 8 kOe near T C[50].…”

Magnetorefractive Effect in Doped La_1-xK_xMnO₃ Thin Films

“…The films become charge and magnetic inhomogeneous at other doping levels. That is why it is necessary to use the effective medium theory for calculation of the MRE in such cases [6].…”