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Information × Registration Number 0212U005735, 0112U005668 , R & D reports Title New physical phenomenon - the pseudomaser effect in electron spin resonance popup.stage_title Head Vorona Igor Petrovich, Registration Date 27-12-2012 Organization Institute of Semiconductor Physics of National Academy of Sciences of Ukrain popup.description2 The phase of absorption and emission spectrum is shifted on 180 at registration using lock-in technique (spectra are inverted). In work EPR spectra of NO32 paramagnetic centers in HAP are experimentally studied at various registration regimes on spectrometer with high-frequency modulation of magnetic field. The spectrum inversion (pseudomazer effect) was found to be observed using hf magnetic field modulation. The effect consists in following. Usual EPR signal is observed at low microwave power. Well-known power-dependence is registered at first under power increasing. But at further increase in power the EPR spectra inversion is observed. The Bloch equations were applied to explain the effect. They were modified to take into consideration influence of magnetic field modulation. Analyses of their solutions with EPR spectra modeling show that signal-response from paramagnetic systems coincides on a phase with magnetic field modulation for the paramagnetic centers with short relaxation times in comparison with the modulation period. For systems with long relaxation times signal-response is late on a phase from modulation and delay increases with increase in microwave power. In this case the signal-response can be presented in the form of superposition of two signals - in-phase and quadrature. In-phase signal coincides on a phase with modulation while quadrature one is shifted on 90 degrees. The contribution of the last increases with microwave power increasing and it is dominant for paramagnetic centers with long relaxation times under saturation conditions. Quadrature signals exhibit unusual saturation curves that are shown in their inversion at increase in microwave power. Using simultaneous registration of quadrature and in-phase EPR signals at definition of relaxation times by method of continuous saturation gives the chance to determine separately spin-lattice and spin-spin relaxation times of paramagnetic systems. Product Description popup.authors Іщенко Станіслав Степанович Джаган Володимир Миколайович Носенко Валентина Володимирівна popup.nrat_date 2020-04-02 Close