Low temperature EPR spectra of Fe³⁺ centers in ternary layered TlGaS₂ crystal

Abstract

The results of low temperature electron paramagnetic resonance (EPR) study of Fe doped TlGaS 2 single crystal in the temperature range of 5-300 K are presented. Iron was added to the growth mixture in amounts corresponding to a molar ratio Fe/Ga of about 1%. The EPR signal due to Fe 3+ centers located at the centers of GaS 4 tetrahedrons has been observed. A transformation of EPR spectra has been observed on decreasing the temperature, which is attributed to lowering of the number of resonance lines. The simulation of rotational patterns of the resonance fields exhibits a decrease of the number of centers at low temperatures as a contrary to those of isostructural compounds of TlGaS 2 . On comparing the EPR spectra of Fe 3+ centers in TlGaSe 2, it has been revealed that the Tl atoms lose their zigzag alignment observed previously at room temperature and rearranged to equal structural positions on Tl chains on lowering the temperature.

Electron paramagnetic resonance of Dy3+ ions in lead thiogallate single crystals

“…The orientation dependences of these spectra resemble those reported in the EPR studies of Fe 3+ ions in TlGaS 2 crystals [12]. …”

Radicals from the Gas-Phase Pyrolysis of Hydroquinone: 2. Identification of Alkyl Peroxy Radicals

“…[1][2][3] EPR spectra are usually simplified by decreasing the temperature at which the EPR spectrum is registered, which reduces the complexity of the spectrum by merging the number of resonance lines. 4 Sometimes the EPR spectrum is simplified to a singlet line at low registration temperatures, which is similar to those in powder-phase samples. 5 The spectral intensity, given by the DI/N value, which is the double integrated (DI) intensity of the EPR spectrum that has been normalized (N) to account for the conversion time, receiver gain, number of data points, and sweep width (http://www.brukerbiospin.com/winepr.html?&L)0) is used throughout this paper as a measure of the radical relative concentration.…”

“…The characteristic values for EPR spectra are usually the EPR spectrum g factor and peak-to-peak width, Δ H p−p ( vide infra ). − EPR spectra are usually simplified by decreasing the temperature at which the EPR spectrum is registered, which reduces the complexity of the spectrum by merging the number of resonance lines . Sometimes the EPR spectrum is simplified to a singlet line at low registration temperatures, which is similar to those in powder-phase samples .…”

Thermal and EPR investigations of thallium gallium disulphide single crystal

“…Also a new line at 2430 Oe appears at 95 K and becomes invisible at 180 K. On the other hand, as is seen in figure 3b, we observed just one weak line at 8200 Oe and 20 K, next to the two intensive lines. It becomes wider and more intense at 43 K but then its intensity starts to decrease and gets invisible at 180 K. In our previous study [13], we investigated the angular dependence of all these resonance lines and obtained best fit EPR parameters as g= 2.00, D=0.6000 (0.6300) cm However, no temperature-dependent changes peculiar to structural phase transitions have been observed in EPR spectra of Fe doped TlGaS 2 . As it is known from the previous works [10,11,14], such changes take place in EPR spectra of isostructural compounds of TlGaS 2 (TlInS 2 and TlGaSe 2 ) and contain the processes of splitting (between 800-1500 Oe) and multiplication of the resonance lines (triplet) by lowering the temperature and passing through the possible phase transition temperature assigned for those compounds in literature.…”

“…The fundamental structural unit of a layer is the Ga 4 S 10 polyhedron representing a combination of four elementary GaS 4 tetrahedrons, which are linked together by common chalcogen atoms at the corners. The Fe 3+ ions substitute for the Ga 3+ sites in the centre of the GaS 4 tetrahedrons [13]. This should keep the local site symmetry since no charge compensation is necessary and also the ionic radii of the two ions are almost equal (0.061 nm for Ga 3+ and0.063 nm for Fe 3+ ).…”