Giant magnetorefractive effect in magnetic granular CoFe-MgF alloys

Optical and magnetooptical properties of CoFeB/SiO2 and CoFeZr/Al2O3 granular magnetic nanostructures

“…In the case of transmitted light, the rotation of the plane of polarization is given by (5) where l is the layer thickness and λ is the wavelength of light.…”

“…Among them the magnetoresistance effect [1], inverse or positive magnetoresistance [2], spin-dependent electron tunneling, high dielectric losses in the microwave range [3], the anomalous Hall effect [4], and the large magnetorefractive effect [5] should be mentioned. A number of papers aimed at revealing and investigating possible correlations between the magnetic properties, magnetotransport, and linear and nonlinear optical and magnetooptical properties of granular nanostructures have appeared [5][6][7]. Particular attention centers presently on the behavior of nanostructures near the percolation threshold, because in this region the most pronounced changes in their characteristics are observed.…”

Spin-dependent tunnelling at infrared frequencies: magnetorefractive effect in magnetic nanocomposites

“…Besides traditional MO effects connected with spinorbit interaction, a new magneto-optical effect in nanostructured materials with large magnetoresistance, the so-called magnetorefractive effect (MRE), was discovered [13] and studied thoroughly [13][14][15][16][17][18][19][20][21]. The effect consists of changes in optical properties of systems with large magnetoresistance when they are magnetized.…”

Electrical properties of ferromagnetic-insulator nanocomposites

“…Scientific interest to the such nanocomposites is caused by the fact that presence of the nanometer-sized ferromagnetic particles leads to appearance of unique electrical, galvanomagnetic, optical and magneto-optical properties. As examples of the most significant properties, we can note the tunneling magnetoresistance reaching 12-13% at room temperature [1], the giant Hall effect, which is four orders of magnitude greater than the given effect in pure metals [2], the magnetorefractive effect which is two orders of magnitude greater than the traditional magneto-optical effects [3] and others phenomenon [4][5]. This paper is devoted to analysis of our experimental data on the study of electrical properties of ferromagnetic-insulator nanocomposites and the mechanisms of charge carrier transfer established in them.…”

“…The changing of charge transfer mechanism for the studied composites is observed in the temperature range of ~ 200 -300 K. This is expressed in a deviation from the law «1/4» for conductivity. A theoretical model of inelastic tunneling through amorphous dielectric layers was used by the authors [3,4] to explain the temperature dependence of the conductivity of the granular composites located before of the percolation threshold. According to this model, the observed experimental temperature dependences of conductivity are explained by resonant tunneling through a chain of localized states in an amorphous insulating layer in tunnel junctions, and the temperature dependence of the conductivity in a channel containing n impurities has a power-law form:…”