WO2013013674A1

WO2013013674A1 - Magnetizable single- and multilayer systems, and production and use thereof

Info

Publication number: WO2013013674A1
Application number: PCT/DE2012/200048
Authority: WO
Inventors: Kah Ming MOK; Heidemarie Schmidt; Camelia SCARLAT; Ines WEBER
Original assignee: Helmholtz-Zentrum Dresden - Rossendorf E.V.
Priority date: 2011-07-27
Filing date: 2012-07-27
Publication date: 2013-01-31
Also published as: DE102011052217B4; DE102011052217A1

Abstract

The invention describes the design of an arrangement of a magneto-optical system in which a specific polarization of the reflected or transmitted wave is achieved for a predefined wavelength of the incident electromagnetic wave. The arrangement according to the invention and the use method allow use for optimizing the design of a magneto-optical system in order to achieve the "target" polarization of the reflected or transmitted wave, or of a magneto-optical storage device or of a magnetic field sensor. Furthermore, the invention makes it possible to construct a magneto-optical modulator or a multiplexer comprising a magneto-optical component.

Description

description

Magnetisable single and multi-layer systems, their production and use Technical field

The invention relates to an arrangement of nnagnetisierbaren single and multi-layer system, especially for the magneto-optical coupling of electromagnetic waves to a magnetizable single and

Multilayer system with magnetizable individual layers, as well as their production and use.

State of the art

The magnetic moment in magnetizable materials depends

preferably parallel to the field lines of the magnetic field H out.

A magnetizable single and multi-layer system consists of one or more stacked layers, of which at least one layer is magnetizable.

Ferromagnetic materials, e.g. Iron, nickel, cobalt, have one

Memory for the externally applied magnetic field H and can after switching off the external magnetic field H have a magnetic order, ie a finite magnetization M _j . Setting a spontaneous magnetic order is temperature dependent and occurs in ferromagnetic materials below the Curie temperature.

The temperature dependence of the magnetic order is in

Erase process used before each write in magneto-optical discs. Magneto-optic discs are magnetically written and optically read, combining the advantages of magnetic and laser technology for capturing and storing data. When erased, the magneto-optical disks are locally heated with a laser writing beam above the Curie temperature. After cooling, the magnetization remains present. The differently magnetized areas reflect light differently by the magneto-optic Kerr effect, so that the

Reading also a laser beam, the laser reading beam, can be used. The laser reading beam has a lower power than the laser Write beam because he does not need to heat the material. Magneto-optical storage media are expensive but very good backup memories.

Due to lack of capacity and / or high costs are the

Future prospects for magneto-optical storage media relatively low. Currently, no current developments are expected in this direction.

The electrical resistance of magnetizable multilayer systems

depends on the orientation of the magnetization in the individual layers of the multilayer system to each other. This magnetic field dependence of the resistance is z. B. in magnetoresistance sensors, that are

magnetizable multilayer systems in which the magnetization of at least one layer in one direction depends reversibly on an externally applied magnetic field H used.

Multilayer systems consisting of two ferromagnetic layers, which are separated by an insulating layer, show the effect of

Tunnel magnetoresistance (TMR). The electrical resistance of TMR structures depends on the magnetic orientation of the two

ferromagnetic layers to each other. TMR structures are in

Read heads used in hard drives with high capacities. TMR structures are also used in magnetic sensors and as storage elements in

Magnetic random access memory (MRAM) is used.

Multilayer systems consisting of two ferromagnetic layers, which are separated by a non-magnetic metal intermediate layer, show the effect of giant magnetoresistance (GMR). The electric

Resistance of GMR structures depends on the magnetic orientation of the two ferromagnetic layers to each other. The GMR effect is smaller than the TMR effect. GMR structures are used in read heads of hard disks which have a smaller capacity than the disks with read heads with TMR structures.

The magneto-optical properties of magnetizable single and

Multilayer systems depend on the size and direction of the

Magnetization in the individual layers from.

Magneto-optics means the interaction of

electromagnetic waves with magnetizable materials. Magneto-optic effects are given as standard with respect to the orientation of the magnetization of the individual layers to the propagation direction of the electromagnetic wave. Thus, a distinction is made between longitudinal (Faraday effect), transverse and polar magneto-optical effects.

[001 1] US 4650290 A, US 3680065 A, US 5538801 A and US 6143435 A

describe the magneto-optical properties of magnetizable single, two or three-layer systems depending on the

Magnetization of the single layers. The disadvantage of these four applications is that they depended on the dependence magnetooptical properties of

Single layers of magnetizable single, two or

Three-layer system of the characteristics of the incident

electromagnetic wave (for example, wavelength or

Polarization state) or the thickness of the magnetizable single layers do not take into account.

The magneto-optical effects are quantum-mechanical in nature and can be determined by means of the MAXWELL equations and the material-dependent conductivity tensor σ, dielectric tensor ε and magnetic

Permeability tensor μ describe. Knowing the dependent on the wavelength of the electromagnetic wave material tensors leads to a description of how electromagnetic waves in a

spread magnetizable single and multi-layer system.

A modulator impresses information to an electromagnetic wave, e.g. by varying the intensity, phase, polarization or direction of the electromagnetic wave. A switch, e.g. The optical isolator is therefore a special case of a modulator for switching on and off electromagnetic waves.

Generally referred to as birefringence (dichroism) is an optical phenomenon that occurs in many anisotropic media and by different propagation of electromagnetic waves for

different orientations of the polarization vector distinguishes.

Birefringence occurs e.g. by magnetooptical coupling of a

electromagnetic wave to magnetizable single and Multi-layer systems in an external magnetic field and / or by electro-optical coupling of an electromagnetic wave to electrically polarizable single and multi-layer systems in an outer

electric field.

An example of an application for the electro-optical coupling are Pockels and Kerr cells. In them, the refraction and polarization behavior of a material is changed linearly (Pockels effect) and quadratically (Kerr effect) by an externally applied electric field. Be typical changes in the refractive index Δη / η ~ 10 ^'5. After propagation of the

electromagnetic waves by a distance of 10 ⁵ wavelengths, this results in a phase shift of 2ττ. Materials for Pockels cells are usually crystals, eg NH ₄ H ₂ PO, LiNbO ₃ , LiTaO ₃ , KH ₂ PO. Materials for Kerr cells are mostly isotropic point-symmetric media (gases, liquids, certain glasses). The electro-optical effects are used in variable refractive index retardation plates

Phase modulation, to change the light polarization and to change the light intensity as well as used in lenses with variable focal length. Achievable modulation frequencies range from a few hundred MHz to a few GHz. The modulation frequency can be increased by integrated optical design, z. B. integrated-optical phase modulator, integrated-optical interferometer and integrated optical

Directional. However, an electro-optic modulator has one

Disadvantageously, that it is characterized by direct current (DC) drift (NAGATA, Hirotoshi, et al., Estinnation of direct current bias and drift of Ti: LiNbO3 optical modulators, J. Appl. Phys., 1994, Vol , P.1405-1408.) And optical damage (English: Optical Damage) suffers. Therefore, it is difficult to stably operate it for a long period of time, or it costs much to avoid deterioration of its electro-optical characteristics.

An example of application for magneto-optical coupling are optical

Insulators. These are optically isotropic and magnetizable materials, which become optically anisotropic by applying a magnetic field and the polarization direction of the electromagnetic wave as a function of rotate the angle between the propagation direction of the electromagnetic wave and the magnetic field exactly 45 ° between both ends of the magnetizable material. At both ends of the optical isolator are polarizing filters, which are rotated by 45 ° to each other. Electromagnetic waves of appropriate wavelength can pass unobstructed through the rear polarizing filter, while the polarization direction of back-reflected electromagnetic waves has been rotated by 90 ° and these can not pass the front polarizer. Since the Faraday rotation of light depends strongly on the wavelength, optical isolators function perfectly only at a certain wavelength; at all other wavelengths, light is also transmitted in the opposite direction and part of the light is filtered out in the forward direction by the analyzer. Recently, various optical communication systems have been disclosed in which an electric field is applied from an antenna as a source of a radio frequency signal to an electro-optical modulator (DE 60307919 T).

Another example of application for magneto-optical coupling are

Magneto-optical modulators in which the modulating magnetic field is generated with a current-carrying coil. The

Modulation speeds are slower than one

electro-optical modulator and not higher than a few kHz. The heating of the current-carrying coil is also disadvantageous. Therefore, the magneto-optical modulator becomes low only for one

Response magnetic field sensor or an electric current sensor used (DORIATH, G., et al. A sensitive and compact magnetometer using Faraday effect in YIG waveguide@1.3 μηη. J. Appl. Phys. 1982, Vol. 53, No. 1 1, Pp. 8263-8265.).

DE 60307919 T discloses a magneto-optical modulator which is operated in a wide frequency range and which is free from the disadvantages of the electro-optical modulator, such as the DC drift and the optical impairment. In the magneto-optical modulator according to DE 60307919 T, a biasing magnetic field is aligned almost along the light propagation direction, while the magnetic RF field is oriented in a direction different from the light propagation direction. Furthermore, the magnetic RF field is generated by a

magnetic field induced by an electrical RF current signal generated on a magnetizable line, e.g. a stripline

(including microstrip line), a coplanar line or a coaxial line. Further, according to DE 60307919 T T2, an RF signal can be fed from an antenna into an RF magnetic field generator, thereby building up an optical communication system for wireless RF signals.

Phenomenologically, it was found that magneto-optical effects in

magnetizable materials very much on the wavelength of

depend on electromagnetic wave. So can the magneto-optical

Modulator according to DE 60307919 T be used only at a frequency close to the ferromagnetic resonance frequency of the magnetizable material of the magnetizable line.

Phenomenologically, one can see the magneto-optical effects by the

Describe adjacent diagonal elements in the magneto-optical dielectric tensor ε. Provided that no further optical anisotropies occur, ε can be decomposed into a symmetrical and an antisymmetric component. The antisymmetric component of the magneto-optical Dielektrizitätstensors ε contains the magneto-optical coupling, which is a complex material constant and in the first

Approximation proportional to the sample magnetization is assumed.

As long as the complex magneto-optic coupling constant of a magnetizable material is known only qualitatively, the propagation of electromagnetic waves in the magnetizable material can not be described quantitatively.

The wavelength dependence of the asymmetric portion of the

Magneto-optic dielectric tensor ε can theoretically be predicted for various magnetizable materials. A comparison between theory and experiment shows, however, that the asymmetric component of the magneto-optical dielectric tensor ε depends on strains in the magnetizable single and multi-layer structure and that this Influences on the net spin polarization and the electronic band structure of the magnetizable material must be taken into account when calculating the asymmetric component of the magneto-optical dielectric tensor ε.

Multiplexing methods are methods for signal and message transmission in which several signals are combined and simultaneously via a

Medium, e.g. via a cable, cable or radio link. Wavelength Division Multiplexing (WDM) technology is an optical frequency division multiplexing technique that uses different wavelengths of light to transmit multiple signals in parallel. In principle, each signal to be transmitted of a light frequency is modulated during wavelength division multiplexing. For telecommunications are called

Wavelengths virtually all wavelengths of the optical windows of the

Telecommunications at 850 nm, 1300 nm and 1550 nm used. Thus, when using three light frequencies, three signals can be transmitted simultaneously. The optical coupling element, the wavelength division multiplexer, bundles the different wavelengths of light and transmits the whole

Luminous flux, which contains all discrete wavelengths, over one

Fiber optic cable to the receiving site, where he in demultiplexer means

Filtering techniques is separated into the individual channels. The problem is the realization of suitable multiplexers and demultiplexers. So far, electro-optical effects are used for this purpose.

So far, no suitable multiplexers and demultiplexers, which

use magneto-optical effects, for the optical windows of

Telecommunication at 850 nm, 1300 nm and 1550 nm realized.

According to DE 69413308 T is a magneto-optical element with

Electro-optical modulators combined.

The non-contact sensor principle of magneto-optics opens up possibilities for cost reduction for the areas of system installation and maintenance in information technology, vehicle technology, mechanical engineering and medical technology. However, sensors are based on others

physical principles many times the magneto-optical sensors

preferred because often the application technology actually secondary Factors like price, expertise of the developer or the time until the

Availability of the complete solution plays the decisive role.

The focus of the development is magneto-optical sensors for the visualization of stray magnetic fields. The Earth's magnetic field at the Earth's surface is 0.031 kA / m. As sensor materials for magneto-optics, e.g. monocrystalline ferromagnetic garnet layers based on bismuth substituted rare earth iron garnet of stoichiometry

(Bi, SE) 3 (Fe, Ga) 5Oi2. These magneto-optical sensors have a specific Faraday rotation of up to 1.3 μηη in transmission

(Wavelength λ of the polarized electromagnetic waves λ = 590 nm, a dynamic range in the visualization of magnetic field strengths between 0.03 to 200 kA / m, a high spatial resolution in the low μηη range and good transparency in the visible spectral range from about λ> 530 nm.

Magneto-optical sensors can be classified according to their imaging properties in "analog" imaging and "binary" imaging sensors.

Analog imaging magneto-optical sensor layers are able to

small magnetic differences of the examination object in

depict different brightness contrasts. About the

Differences in brightness is in principle a statement about the strength of the

observed magnetic fields possible.

"Binary" imaging sensor layers have a jump in their hysteresis loop. This means that even very small magnetic fields are sufficient to reach the saturation magnetization of the layer - which also leads to the maximum Faraday rotation. These sensors can only map magnetic fields according to the "yes-no" principle.

Presentation of the invention

[0030]

Technical task

The object of the invention is an arrangement of a magneto-optical

Specify a system in which for a given wavelength of the incident electromagnetic wave a certain polarization of the reflected or transmitted wave is reached. The invention describes the design of the magneto-optical system to achieve the "target" polarization of the reflected or transmitted wave.

Furthermore, possible applications for this magneto-optical

System specified.

Under electromagnetic waves are not only white light,

monochromatic visible, ultraviolet or infrared light

but the totality of all electromagnetic waves of different energies or frequencies or wavelengths.

Figure Description

The arrangement will be described with illustrations.

Figure 1 shows on both sides of the structure of a magnetizable

Single layer system. The magnetizable single layer system comprises an optional carrier T and a magnetizable single layer S. When using a carrier T, as shown in Figure 1, forms between the carrier T and the single layer S, a boundary layer or an interface G from. The thicknesses of these layers and of the carrier are denoted ds, de dT. Electromagnetic waves hit under the

Angle of incidence α on the magnetizable single layer S and are reflected with the reflection angle a 'and transmitted with the refraction angle ß through the single-layer system.

For individual uses, for. B. for the determination of the magneto-optical

Coupling constant & a magnetizable single layer, it may be useful that only monochromatic light, which in one

Monochromator 10 is generated, and optionally subsequently polarized in the polarizer 11 is used.

The two parts of Figure 1 are intended to illustrate that the thickness ds of the layer S is relevant to the polarization result of the reflected wave.

Figure 2 shows on both sides the structure of a magnetizable

Multilayer system. The magnetizable multilayer system comprises an optional carrier T and at least two magnetizable single layer Si. When using a carrier T, as shown in Figure 2, forms between the carrier T and the adjacent to the carrier single layer Sn a boundary layer or an interface G from. The thicknesses of these layers and of the carrier are denoted dsi, de dT. Also, between the individual layers Si and Si + i, with 1 <i <n-1 and n, the number of magnetizable layers, interfaces which, if the layers Si consist of metals, form opposite the boundary layer G.

between carrier T and layer S _{n are} very thin. The layers Si and S _n in the left and Si and S _n in the right figure 2 are optional.

Analog to Figure 1, electromagnetic waves hit under the

Angle of incidence α on the magnetizable single layer Si and are reflected with the reflection angle a 'and transmitted with the refraction angle ß through the multilayer system.

The two parts of Figure 2 are intended to illustrate that the order of the layer Si is relevant to the polarization result of the reflected wave.

Figure 3 illustrates a possible use of this method for small objects with nonplanar interfaces, e.g. If these are irradiated with an electromagnetic wave having a wavelength which is smaller than the object size, and the size of the "light spot" 22 is less than the wavelength, the method for

Determination of the properties of these nanoparticles can be used because the bold areas can be regarded as parallel to each other interfaces. The material 21 in which the magnetizable material 22 is embedded is optional.

FIG. 4 shows a possible a) series connection or b)

Parallel connection of individual magnetizable single or

Multilayer systems, which can be combined and expanded as desired and used in magneto-optical multiplexers.

Main features of the solution

The object is achieved by using a magnetizable single and multilayer system 1 consisting of an optional carrier T and at least one magnetizable single layer S, Si. The

Magneto-optical properties of the magnetizable single layers are by the magnetization ^M <of the layer Si and the thickness di the nnagnetisierbaren layer and by the wavelength-dependent magneto-optical Dielektrizitätstensor ε given.

The main diagonal elements of the dielectric Tensor ε, the single layer Si are by the wavelength-dependent refractive index N, and the

Absorption index K of the single layer Si along the major axes (x, y, z) given a Cartesian coordinate system. In the non-diagonal elements of the complex magneto-optical Dielektrizitätstensor ε, the single layer Si is the vector product of the complex

wave dependent magneto-optical coupling constant ^{"^} 'ö .SS ^r and the wavelength-independent magnetization ^Μ' ^~ ^ ^M ^ ^M y ^M - ^ d _he monolayer Si.

The magnetization ^M <is determined by means of independent

Magnetization measurements determined and can be linear from the outside

Magnetic field ^ ΊΙ ^ or non-linear depend on the external magnetic field.

For the determination of the wavelength-dependent magneto-optical

Coupling constant Q of the single layer S, Si is, as in Fig. 1st

represented, the Müller-matrix polarimetry in reflection or transmission in the magnetic field under saturation magnetization conditions preferably at least two differently thick, but equally strained, magnetizable single layers Si same composition and crystal structure performed on the same carrier material T. After that, the

Mueller matrix measured using the dielectric tensor of all individual layers Si, here the magnetizable single layer S and the carrier material T modeled and wave-dependent magneto-optical

Coupling constant ß ^{^"(o.} ^ Ö ^v ö.-), _he d magnetizable single layer S, Si with simultaneous knowledge of their magnetization ^M <extracted.

When using a magnetizable single-layer system on a support T, as shown in Figure 1 - left partial illustration, or when using a magnetizable multilayer system on a support T, Figure 1 - shown right partial illustration, forms between the carrier T and the at the Support adjacent single layer S or S _n, a boundary layer of thickness dG or an interface G from. It is also forming between the individual layers Si and Si + i, where 1 <i <n-1 and n denotes the number of individual layers Si, interfaces which, if the

Single layers Si of metals are compared to the boundary layer G between the carrier T and layer S _{n are} very thin and can be neglected in the modeling, if the wavelength of the

electromagnetic wave is large against the thickness dG of the boundary layer.

The wavelength-dependent magneto-optical coupling constant Q is a thickness-independent material parameter. Only if the wave-dependent magneto-optic coupling constants ß

), _from

magnetizable individual layers Si of different thickness d, but with the same strain, same composition and same crystal structure on the same carrier material T are the same, the influence of boundary layers G between the carrier T and the single layer Si in the determination of the wavelength-dependent magneto-optical coupling constant Q of the single layer Si excluded become.

The calculation of the Müller matrix of a magnetizable single or

Multilayer system using the magneto-optical

Dielectricity tensor ε, and the thickness d, the individual layers Si and the dielectric tensor ετ and the thickness dT of the carrier T allows a theoretical prediction of the magneto-optical response of

magnetizable single and multi-layer system to an incident angle a incident electromagnetic wave with a

predetermined wavelength λ.

The calculation of the Müller matrix also allows a prediction

with respect to the design of the dielectric tensor ε,, the thickness d, and the arrangement of the individual layers Si of a single and multi-layer system so that the reflected or transmitted electromagnetic wave reaches the "Zie - polarization. Optionally, as shown in FIG. 3, the magnetizable single or multi-layer system can not contain plane-parallel interfaces between the individual layers Si. In this case, the magnetizable single or multi-layer system is segmented. The

Electron-magnetic wave meets segmented areas. These individual segments 22 are plane-parallel and each individual layer Si in this segment 22 has a constant thickness di. For each segment 22, the Mueller matrix can be calculated using the magneto-optic dielectric tensor ε, and the thicknesses d, the monolayers Si and the magneto-optical response of each segment 22 of the magnetizable single or multilayer system to an electromagnetic incident on the segment 22 at the angle of incidence α Wave with a given wavelength λ

be predicted. These spatially resolved magneto-optical measurements can be used to characterize magnetizable materials with non-plane-parallel interfaces 20 in different host materials 21

be used.

Advantageous effects

[0051] With the arrangement according to the invention and the invention

Methods can be the process-dependent magneto-optical

Coupling constants for individual spectral ranges are determined.

This is the identification of spectral regions in which the

Coupling of the incident electromagnetic waves is very strong, only possible. A major advantage is that in the applications of the arrangement produced by this method, the requirements for the specific magneto-optical single or multi-layer system with respect to angle of incidence of the light, polarization state of the light, frequency of the light are taken into account.

The inventive method allows easy adjustment of the desired target polarization.

The arrangement according to the invention can be used to measure the

Magnetic field gradients and used to determine the magnetization of the individual layers.

Another possible use of the method is the targeted

Magneto-optical modulation of individual wavelengths and the

magneto-optical modulation of several wavelengths of the incident light by series or parallel connection of several of these arrangements for individual wavelength ranges.

The inventive method allows the optimal design of magnetizable single and multi-layer systems. embodiments

Optimization of the design of the magneto-optical system to achieve the "target" polarization of the reflected or transmitted wave.

The "target" polarization of a reflected or transmitted

Electromagnetic wave can be optimized by calculating the Mueller matrix of the magneto-optical system as a function of the thickness d, d of magnetizable single layers S, Si and analyzing the magneto-optical response with respect to the "target" polarization.

Optimization of a magneto-optical memory

Choice of a magnetizable material of thickness d, and with the

Magneto-optical Dielektrizitätstensor ε, for the magneto-optical memory, which for electromagnetic waves with the wavelength λ and the polarization state of the laser reading beam as large as possible

has magneto-optical response to the "target" polarization.

Optimization of a magneto-optical sensor

Choice of a magnetically anisotropic material whose easy axis of magnetization in the direction of the magnetic to be visualized

Stray field shows and its magneto - optical response is optimal with respect to the "Zie - polarization of the reflected or transmitted electromagnetic wave.

Optimization of a magnetic field sensor

The "target" polarization must be magnetized along one of the

Major axes x, y, z of a Cartesian coordinate system change so that the components ( ^M ^ ^M y ^{> M} =) of the magnetization are determined by interrogation of different "target" polarizations, thus one can conclude on the applied external magnetic field ^H <.

Development of a magneto-optical modulator

The development of a material having a spontaneous magnetization without an externally applied magnetic field, for a

magneto-optical modulator. The magnetization of the to be developed Materials can follow the modulating magnetic field synchronously by applying the modulating magnetic field with respect to its direction and amplitude change. The material to be developed must simultaneously have optimized magneto-optic properties so that the "target" polarization is achieved for an electromagnetic wave of given wavelength.

Development of a multiplexer with magneto-optical component

Use of a magneto-optical modulator, which with respect to such optimized magneto-optical properties of the magneto-optical

Dielectricity tensor ε, and / or with respect to the thickness d, d, that the "Zie - polarization for electromagnetic waves of different wavelengths λ and / or the same output polarization or for electromagnetic waves of the same wavelength and different output polarization is different. To achieve the "target" polarization, several magneto-optic modulators may be combined in series or in parallel.

LIST OF REFERENCE NUMBERS

[0062]

Table 0001

Magnetisable single or multi-layer system

10 monochromator

1 1 polarizer

12 polarization state before interaction with 1

13 polarization state after interaction with 1

14 Analyzer or other applications

20 Magnetizable material with non-plane-parallel interfaces

21 material in which the magnetizable material 22 is embedded

22 segment with plane-parallel interfaces interface

support material

S, Si Magnetizable layer x, y, Cartesian coordinate system

Thickness of the carrier material

Thickness of the interface

Thickness of the magnetizable layer α, a angle of incidence, reflection angle β angle of refraction

H External magnetic field

M, magnetization of the layer S,

Magneto-optical Dielektrizitätstensor the layer S,

Dielectric tensor of carrier T

Ni, Ki refractive index and absorption index of the layer S,

Qi Magneto-optic coupling constant of the layer S,

Photon energy of the electromagnetic wave E = hv = h ^* c ^* λ- ¹ λ Wavelength of the electromagnetic wave

Claims

claims

1. Magnetisable single or multi-layer system for magnetic field-dependent manipulation or modulation of incident electromagnetic waves, comprising at least one magnetizable single layer Si with a thickness di, optionally on a magnetizable or non-magnetizable

Support material T may be applied to the defined magneto-optical coupling of the incident electromagnetic wave to the magnetizable single or multi-layer system, characterized in that the

Polarization state of the reflected or transmitted electromagnetic waves as a function of their energy E by the size and direction of

Magnetization ^M <and can be manipulated or modulated by the magneto-optical coupling constant Q of the individual layers Si of the magnetizable single or multilayer system.

2. Magnetisierbares single or multi-layer system according to claim 1_, characterized in that the single layer Si has a spontaneous magnetization ^ (°) and / or that the single layer Si by an externally applied

Magnetic field H is magnetized, wherein the applied magnetic field can be constant over time or variable.

3. Magnetisierbares single or multi-layer system according to claim 1 or 2, characterized in that different magnetizable single and / or multi-layer systems 1 can be connected in combination in series and / or in parallel.

4. Method for predicting the state of polarization of the reflected or transmitted wave of the magnetizable single or multilayer system 1 using the magneto-optical dielectric tensor ε, each

Single layer Si of the single or multi-layer system 1 as a function of the properties, wavelength λ and polarization state 12, the incident electromagnetic waves, wherein elements of the magneto-optical

Dielectric tensor ε, vector products from previously determined

wavelength-dependent magneto-optic coupling constant Q and wavelength-independent magnetization ^M <of the individual layers Si of the single or multilayer system 1.

5. Use of the nnagnetisierbaren single or multi-layer system 1 according to any one of claims 1 or 2 for the non-destructive measurement of

Magnetization ^M <of all individual layers Si of a magnetizable single or multi-layer system 1 using the measured properties (polarization states 12 and 13 and the wavelength λ) of the incident electromagnetic waves and of the magnetizable single or

Multilayer system 1 reflected or transmitted wave, wherein the

Magneto-optical coupling constant Q of all individual layers Si of the magnetizable single or multi-layer system 1 must be known.

6. Use of the magnetizable single or multi-layer system 1 according to any one of claims 1_ or 2 for measuring time-constant or variable magnetic fields H, wherein the linear or non-linear

Connection between the known magnetization ^M <at least one single layer Si of the magnetizable single or multi-layer system 1 and an external magnetic field H must be known.

7. Use of the arrangement according to one of claims _ to 3 than

magneto-optical sensor, magneto-optical memory or magneto-optical modulator.