Kerr Effect Spectra Research Articles

Recording of low-frequency vibrations of water molecules by four-photon polarization Raman spectroscopy

A description is given of a spectrometer capable of recording panoramic Raman-induced Kerr effect (RIKE) spectra in the range of frequency offsets from – 600 to 1600 cm− 1. The RIKE spectra of low-frequency intermolecular vibrations of liquid water (with lines at frequencies 16, 71, and 82 cm− 1) are reported for the first time and the results are given of a determination of the spectroscopic parameters of the corresponding continuous Raman lines.

Raman induced Kerr effect spectroscopy using pulsed lasers

We examine the sensitivity of a coherent Raman spectrometer measuring optically heterodyned Raman induced Kerr effect spectra (OHD-RIKES) with pulsed lasers. Theoretically we show that an optimum OHD RIKES spectrometer is 10 3 more sensitive than quasi-cw stimulated Raman gain spectroscopy (SRGS). Experimental tests of OHD-RIKES using a pulsed probe laser confirm the estimated signal-to-noise ratios. With higher power lasers this technique will provide sufficient sensitivities to detect particle densities as low as 10 11 cm -3.

Electronic and magneto-optical properties of ion beam sputtered rare earth-FeCo thin films

Amorphous rare-earth-transition-metal thin films have been deposited in ultrahigh vacuum by ion beam sputtering. Film composition and purity are controlled by Auger electron spectroscopy and X-ray photoemission spectroscopy. X-ray and ultraviolet photoemission valence band spectra are compared with polar magnetooptical Kerr-effect spectra in the photon energy range 0.5 >

Magneto-optical properties of Ga-substituted magnetoplumbites

The complex polar Kerr effect spectra in diamagnetically substituted hexagonal ferrite system PbFe12−xGaxO19 (x= 0, 1, 3,4) at 290 K between 2 and 5·5 eV are studied. The previously published data on optical constants in this system are employed to obtain the offdiagonal permittivity tensor element spectra.

Complex polar Kerr effect spectra of magnetoplumbite

The paper presents the complex polar Kerr effect spectra in hexagonal ferrite PbFe12O19 (magnetoplumbite) at 290 K between 2 and 5·5 eV. The spectra are compared with the corresponding spectra in Li0.5Fe2.5O4. The previously published data on optical constants of magnetoplumbite are employed to obtain the off-diagonal permittivity tensor element spectra. The effect of nonzero angle of incidence in uniaxial magnetic crystals on the observed polar Kerr effect is briefly discussed.

The magneto-optical polar Kerr effect and birefringence spectra in PrFeO3between 2 and 5.6 eV

The complex polar Kerr effect and the effect of birefringence in PrFeO3 are reported between 2 and 5.6 eV. It is shown that the birefringence observed in transmission has its origin in the electronic transitions involving 3d levels of Fe3+ which are situated in the near-ultraviolet spectral range. The low-energy Kerr ellipticity and the associated Faraday rotation in PrFeO3 are of opposite sign compared to the other orthoferrites studied so far. This situation is analogous to that observed in Pr3+ and Nd3+ substituted iron garnets. It is concluded that the mechanism responsible for the anomalous Faraday rotation in Pr3+ and Nd3+ iron garnets does not require the presence of tetrahedral iron ions.

Optical Kerr effect induced by a Raman resonance in liquid oxygen

A study was made of the optical Kerr effect spectra of liquid oxygen at T = 80 °K in the region of a resonance with an intramolecular vibration of O2 at Ω0 = 1552 cm−1. In addition to a strong resonance line at Ω0, the spectrum included a weak resonance shifted by 4 cm−1 from Ω0 due to the splitting of the ground electronic state of oxygen because of the interaction of spins of two unpaired electrons. It was found that the nonresonant electronic part of the polarizability of oxygen was small compared with the resonant contribution.

On the history of magneto-optics

Stimulated by technological prospects of high-density magneto-optical (MO) recording and by fundamental research on magnetism, a wealth of experimental data on MO Kerr spectra had been collected until the beginning of the nineties. The theoretical explanation of magneto-optical Kerr effect (MOKE) spectra because of first-principles band-structure calculations was at that time in its infancy, and consequently all the insight that theory could give in the microscopic mechanism leading to large Kerr rotations was mainly speculative, because nothing could be proven by first-principles calculations. This situation has profoundly changed, due to the rapid development of first-principles computational research on MO Kerr spectra during the nineties.

Magneto-optic Kerr Effect in Ni, Co, and Fe

Magneto-optic Kerr-effect spectroscopy of Ni, Co, and Fe is used to study $d$-band widths and electron spin polarization (ESP). The $d$-band widths determined on the basis of magneto-optic Kerr-effect spectra are wider than those established by photoemission, and the sign of ESP of electrons near the Fermi level in Ni is found to be negative, as predicted by band theory. We discuss the relationship between this work and other recent studies of ESP.

Magneto-optical Investigation of the Band Edge of CdCr2S4 and Related Absorption Measurements on Cr-doped CdIn2S4

The 4T1 and 4T2 crystal-field transitions of Cr3+ have been observed in the absorption spectrum of CdIn2S4(Cr). From the similarity between the temperature dependence of the 4T2 band and the reported blue shift of the absorption edge of CdCr2S4 it is concluded that in CdCr2S4 this edge is caused by the 4T2 absorption band of the Cr3+ ions. The polar magneto-optic Kerr effect between 560 and 700 nm and the Faraday rotation between 800 and 8000 nm are reported for CdCr2S4. The Kerr effect spectrum indicates that the intrinsic band edge of CdCr2S4 is at 1.91 eV at 60°K and shifts to lower energies with decreasing temperature.