The developed technique employs reflection geometry, enabling highfrequency noncontact hall measurements in opaque samples. Jul 20, 2016 quantized magnetoelectric coupling, which induces exotic magneto optical phenomena, awaits to be evidenced in topological insulators. Observation of topological faraday and kerr rotations in. Ieee transactions on magnetics 2012, 48 11, 27772780. The magnetic hysteresis curves measured by moke change the shape depending on the photon energy and therefore deviate from those measured by superconducting quantum. However the results from this thesis demonstrate that magnetic domains in permalloy magnetic nanostructures can still be observed with very good contrast using a magnetooptical kerr effect moke microscope. Localfieldinduced effective magnetic hysteresis of. Magnetooptical kerr measurements in high magnetic fields. Terahertz frequency hall measurement by magnetooptical kerr. Holmarc has introduced a new innovative high sensitivity and high magnetic field spectroscopic faradaykerr effect measuring equipment utilizing the visnir wavelengths.
H 2 i 0, where i h and i 0 are the reflected light intensities in the presence and absence of a magnetic. In general, magneto optic effects break time reversal symmetry locally i. By adding an achromatic quartwavelength retarder to the system and using fourier transformation, the complete magnetooptic parameters, both polar kerr rotation angle 6kand ellipticity k have been measured in the 1. The evolution of the structural, optical, and magnetic properties as a function of postdeposition annealing temperature was performed by hrtem and magneto optical techniques. Landau level spectroscopy of surface states in the topological insulator bi 0. Resonant magnetooptic kerr effect in the magnetic topological insulator cr. Magnetooptical kerr measurements in high magnetic fields and. However the results from this thesis demonstrate that magnetic domains in permalloy magnetic nanostructures can still be observed with very good contrast using a magneto optical kerr effect moke microscope.
Jun 14, 2009 the magneto optical kerr effect moke is a powerful tool for studying changes in the magnetization of ferromagnetic materials. Magnetooptical kerr spectroscopy in ferromagnetic semiconductors. Development of moke spectrometer for magnetooptical studies of. Fe14tas2 exhibited abnormal kerr hysteresis behavior with a. We also present a method to reveal the offdiagonal component of the complex dielectric tensor from. Weller and others published magnetooptical kerr spectroscopy of transition metal alloy and compound films find, read and cite all the research you need on. Polar magneto optical kerr effect moke spectroscopy in the energy range from 1. Magneto photoluminescence probes the electron spin by analyzing the. Magneto optic spectrometer spectroscopic kerr faraday. Optical and magnetooptical study of nickel and cobalt. Magnetooptical fingerprints of distinct graphene multilayers using the giant infrared kerr effect chase t. Magnetooptical kerr effect moke univerzita karlova.
Osa evaluation of the quality of permalloy gratings by. Polar magnetooptical kerr effect moke spectroscopy in the energy range from 1. The magnetooptical studies revealed that the magnetooptical proximity effect due to the hf underlayer to cofeb was weak, but the interfacial contribution of the pt underlayer to the. This work will enable to optimize the magneto optical effects in these layers for maximum sensitivity in ultrafast magnetization dynamics and domain microscopy experiments. We present a theoretical and experimental study of the magnetooptical properties of thin ga,mnas,p layers on gaas substrates with varying phosphorus fractions. A unique apparatus to measure the magnetooptical mo properties of ultra thin magnetic films and multilayers at high fields 20 tesla and low temperatures 2325 kelvin was developed. Magnetooptical kerr spectroscopy is useful to probe the. This confirms that the magnetooptical kerr spectra can also be used to determine the stoichiomry of thin fe 3 o 4 films. Oppeneer and others published magnetooptical kerr spectra find, read and cite all the research you need on researchgate. Comparison of a stoichiometric analysis of fe3o4 layers. An improved type of scanning and analyzer rotating magnetooptic spectroscopy has been designed and constructed. Magnetooptical and optical spectroscopy magnetooptical transversal kerr effect, tke, consists in an intensity variation of the ppolarized light reflected by a sample under magnetization. Terahertz frequency hall measurement by magnetooptical.
Quantitative study of the quadratic magnetooptical kerr. A mirror based polar magnetooptical kerr effect spectroscopy. Magnetophotoluminescence probes the electron spin by analyzing the. Pdf a mirror based polar magnetooptical kerr effect. Paradigm of the timeresolved magnetooptical kerr effect. Mostly fiberoptics is applied to get the light to and from the samples. From the fits of the polar kerr spectra of the fe 3 o 4 layers measured between 1. An experiment on nonlinear laser spectroscopy and magnetooptics at the advanced undergraduate laboratory at berkeley is described. Magnetooptical kerr effect microscopy investigation on. Furthermore, four of the seven main magneto optical mo transitions between 0. A mirror based polar magneto optical kerr effect spectroscopy arrangement. Magnetooptical kerr effects in perovskitetype transitionmetal oxides. Terahertz spectroscopy on faraday and kerr rotations in a. Determination of the sign of g factors for conduction.
A mirror based polar magnetooptical kerr effect spectroscopy arrangement. Electronic structure and magnetooptical kerr effect. Magnetooptical mo spectroscopy in combination with spectroscopic ellipsometry has a great advantage in the investigation of the electronic structure of mfis materials in comparison with other methods. Magneto optical effects in magnetic materials arise due to the optical anisotropy of the materials. It works by measuring changes in the polarization of reflected light. It is used in materials science research in devices such as the kerr microscope, to investigate the magnetization structure of materials. Jun 27, 2002 we report on the timedomain terahertz thz magneto optical kerr spectroscopy in the frequency range from 0. Holmarc a216 frkr test station provides standardized testing solution to fit wide ranging optical rotation measurement applications. It describes the changes to light reflected from a magnetized surface.
The source of this optical anisotropy is the magnetisation m within surface domains which can be influenced by external forces such as magnetic fields. Moke microscope magnetooptical kerr effect microscope pdf. Aging of rubrene layers in nirubrene heterostructures. The agreement between the data and the model led us to conclude that abovebandgap magneto optical kerr rotation in ferromagnetic ga,mnas is determined by interband transitions.
Fe14tas2 exhibited abnormal kerr hysteresis behavior with a strong sensitivity to the probing photon energy. It uses an additional mirror which eliminates the need for an electromagnet pole piece with an axial hole and allows for. Magneto optical kerr spectroscopy in ferromagnetic semiconductors. After fourier transformation, the magnetooptical parameter of polar kerr rotation angle, e is obtained. Characterization of organic thin films on ferromagnetic substrates by spectroscopic ellipsometry and magnetooptical kerr effect spectroscopy. Investigation of the stoichiometry of mbegrown fe3o4. The magnetic hysteresis curves measured by moke change the shape depending on the photon energy and therefore deviate from those measured by superconducting quantum interference device squid. The prime advantage of kerr spectroscopy is that this technique is only sensitive to the magnetic layer and insensitive to the substrate. Motivation for a high field mo kerr probe based on direct optics. Electronic structure and magneto optical kerr spectra of an epitaxial ni 54. Magnetooptic kerr effect of strongly correlated electron. Magneto optical kerr effect moke spectroscopy in the 1st diffraction order with ppolarized incidence is applied to study arrays of submicron permalloy wires at polar magnetization. An arrangement is described for performing magnetooptical kerr effect moke spectroscopy in polar geometry with a conventional cframe or hframe type electromagnet. Magneto optical kerr effect moke spectroscopy was applied to probe the aging of nirubrene bilayers under ambient atmosphere.
On the other hand, polarizationsensitive spectroscopy using circularly polarized light differentiates between up and down spins and, thus, the measurement of faraday effect, magnetocircular dichroism and magnetooptical kerr effect provides information about the spinpolarized density of states in magnetic materials see fig. We report on the timedomain terahertz thz magnetooptical kerr spectroscopy in the frequency range from 0. Dissertation or thesis magnetooptical spectroscopy of. After fourier transformation, the magneto optical parameter of polar kerr rotation angle, e is obtained.
The study gives a full description of the kerr effect in fe films, and the proposed method can be applied to other magnetooptical coupling systems. The magneto optical studies revealed that the magneto optical proximity effect due to the hf underlayer to cofeb was weak, but the interfacial contribution of the pt underlayer to the. Laser spectroscopy and magnetooptical trapping of rubidium atoms a thesis presented by david e. Fielddependent magnetooptical kerr effect spectroscopy applied to. Therefore, in a first step the signal contribution of the organic film from the contribution of the substrate was separated by field dependent spectroscopy. A theoretical approach combining two methods, the local modes method neglecting the edge effects of wires and the rigorous coupled wave analysis, is derived to evaluate the diffraction. The magnetooptical spectroscopy effects are named after the scientists. The constructed kerr microscope is a homebuild wide field microscope. Investigation of the stoichiometry of mbegrown fe3o4 layers. Laser spectroscopy and magnetooptical trapping of rubidium atoms.
The agreement between the data and the model led us to conclude that abovebandgap magnetooptical kerr rotation in ferromagnetic ga,mnas is determined by interband transitions. In this work we exclusively focused on the magnetooptical kerr effect. Magnetooptical kerr effect moke spectroscopy was applied to probe the aging of nirubrene bilayers under ambient atmosphere. Magneto optical kerr e ect moke photonphoton spectroscopies absorption i. Measurement of the resonant magnetooptical kerr effect. Quantized magnetoelectric coupling, which induces exotic magnetooptical phenomena, awaits to be evidenced in topological insulators. We derived the spectral dependence of the dielectric tensor from experimental data for. The magnetooptical kerr effect moke is a powerful tool for studying changes in the magnetization of ferromagnetic materials. Magneto optical experiments in high fields are done at almost all high field institutes. Bordacs infrared landaulevel spectroscopy in semiconductors with rashba splitting group seminar.
The measurements are done at a near normal incident angle of less than 2 degrees. A comparison between the simulated moke spectra of the heterostructure and the experimental moke spectra recorded at several time intervals after the samples were exposed to the ambient atmosphere demonstrates that the organic layer undergoes slow oxidation. Mar 28, 2017 the kerr ellipticity peak is found to be 2 to 3 times larger than the kerr rotation angle both experimentally and theoretically. Falko, influence of interlayer asymmetry on magnetospectroscopy of bilayer graphene. La1xsrxcoo3, a crystalfieldtransitiontype kerr spectrum is observed that is assigned to the. Transverse magnetooptical kerr effect tmoke measurements provide an additional perspective on magnetocrystalline anisotropy and serve to completely eliminate the possibility of a description in terms of the stonerwohlfarth singledomain model. These are perpendicular and parallel to the optical plane of the incident light on the sample s. Weller and others published magneto optical kerr spectroscopy of transition metal alloy and compound films find, read and cite all the research you need on. Magnetooptical kerr measurements in high magnetic fields and at low temperatures. Butykai back from a 2monthslong optical trap at epfl. We derived the spectral dependence of the dielectric tensor from experimental data for samples. The evolution of the structural, optical, and magnetic properties as a function of postdeposition annealing temperature was performed by hrtem and magnetooptical techniques. A theoretical approach combining two methods, the local modes method neglecting the edge effects of wires and the rigorous coupled wave analysis, is derived to evaluate the diffraction losses due to.
Magnetooptical kerr spectroscopy of transition metal. Magnetooptical kerr effect moke spectroscopy in the 1st diffraction order with ppolarized incidence is applied to study arrays of submicron permalloy wires at polar magnetization. The mo spectroscopy is very sensitive to the crystal structure and chemical composition 46, valence phase transitions 47, as well as induced. Pdf magnetooptical kerr effect spectroscopy based study of. Results from a magneto optical kerr effect moke spectroscopy study of ground state heavyhole and lighthole excitons in gaasal0. Transverse magneto optical kerr effect tmoke measurements provide an additional perspective on magnetocrystalline anisotropy and serve to completely eliminate the possibility of a description in terms of the stonerwohlfarth singledomain model. Kerr effect spectroscopy, magnetic linearcircular dichroismbirefringence, etc. Paradigm of the timeresolved magnetooptical kerr effect for. Experiment and density functional theory calculations s. Spectroscopic ellipsometry and magnetooptical kerr effect. Magnetooptical kerr spectroscopy of transition metal alloy.
Fielddependent magnetooptical kerr effect spectroscopy. Magnetooptical spectroscopy of novel ferromagnetic materials. Here we report the experimental demonstration of the longsought tme effect, which is exemplified by magnetooptical faraday and kerr rotations3,6,7 in the quantum anomalous hall qah states of magnetic ti surfaces1015 by terahertz magnetooptics. Magnetooptic kerr effect moke 18 elements, o and c, with respect to the s and p directions.
Butykai optical trapping of nonspherical particles group seminar. An arrangement is described for performing magneto optical kerr effect moke spectroscopy in polar geometry with a conventional cframe or hframe type electromagnet. In physics the magneto optic kerr effect moke or the surface magneto optic kerr effect smoke is one of the magneto optic effects. Comparison of a stoichiometric analysis of fe3o4 layers by. The same treatment can be used as for the linear pockels effect. Type of investigations polarized light x nonpolarized light, re ection x transmission, di erent properties for di erent polarizations. The kerr spectra were measured by using realtime kerr spectroscopy based on a fibercoupled highspeed spectrometer in the photon energy range of 1. Holmarc has introduced a new innovative high sensitivity and high magnetic field spectroscopic faraday kerr effect measuring equipment utilizing the visnir wavelengths.
1537 19 167 1572 981 1465 1284 429 1173 462 20 1262 341 1425 1122 472 1399 1130 203 309 1109 820 606 1026 91 536 1239 1132 948 969 326 1024