On the theory of multipulsed excitation of spin-echo and free-induction decay signals in angular distribution of oriented nuclei radiation

A theoretical study of the effects of multipulsed NMR on the angular distribution of radiations from oriented nuclei is reported. The perturbation factors of the angular correlation function may be written in general form for any scheme of multipulsed excitation of a nuclear spin system. The irreversible relaxation is taken into account. The experimentally realized situations of spin-echo and free induction decay in angular distribution of nuclear radiation are considered. © 1985 J.C. Baltzer A.G., Scientific Publishing Company

Transient NMR effects in angular distribution of oriented nuclei radiation (ADNR)

The method of concatenating perturbation factors (PF), describing the nuclear spin-system evolution over different time intervals, is presented in consideration of spin-echo and free-induction decay signal formation in ADNR. The spin echo in PAC, formed under pulsed rapid reorientation of a ferromagnetic films magnetization vector is also considered in detail. © 1990 J.C. Baltzer A.G., Scientific Publishing Company

Multiple-pulse NMR of oriented radioactive nuclei under electric-quadrupolar interactions

The formation of the nuclear spin echo in the Angular Distribution of Nuclear Radiations (ADNR) in the presence of combined magnetic-dipole and electricquadrupole interactions (EQI) is theoretically considered. The case of a perturbative EQI in addition to the dominant magnetic hyperfine interaction is analysed. When both interactions are extremely large, with the EQI much greater than the magnetic inhomogeniety, the excitation of spin-echo in ADNR by pulsed rf field, including transitions between a definite pair of quadrupole shifted Zeeman levels is considered. © 1990 J.C. Baltzer A.G., Scientific Publishing Company

Oscillatory free-induction decay signals in the angular distribution of nuclear radiation in ferromagnetic metals under strong inhomogeneous broadening

The problem of the oscillatory free induction decay in the angular distribution of nuclear radiations is theoretically examined for inhomogeneous linewidths, with and without the influence of the skin effect, utilizing the method of concatenation of perturbation factors. The second rank detection tensor applicable to gamma detected pulsed NMRON signals from ferromagnetic metals is examined for axial geometry. Important extensions to the pulse area theorem originally developed only for the first rank detection tensor are proposed for second rank tensors. © 1993 J.C. Baltzer AG, Science Publishers

Pulsed NMRON oscillatory free induction decay signals in the angular distribution of gamma radiation from plated60Co Fe

Results for an inhomogeneously broadened60Co Fe NMRON sample have been obtained for gamma detected single pulse (nutation) and two pulse (free induction decay) experiments in the region of intermediate-to-low R(=ω1/Δ). Here ω1 is the angular frequency measure of the strength of the ferromagnetically enhanced RF field at the nucleus and Δ is the HWHM of the inhomogeneously broadened line. Comparisons of the oscillatory FID signals obtained are made with the theoretical predictions of the following paper [6]. © 1993 J.C. Baltzer AG, Science Publishers

Effect of Secondary Echo Signals in Spin-Systems with a Large Inhomogeneous Broadening of NMR Line

The possibility of comparatively simple and fast determination of characteristic relaxation parameters T1, T2 and T3 for nuclear spin-systems with strong Larmor and Rabi inhomogeneous broadenings of NMR lines using the secondary echo signal effect was experimentally shown. Resides, this method gives opportunity to obtain a valuable infomation on the inhomogeneous NMR broadening which reflects the character of magnetic field microscopic destribution in such systems, as example, multidomain magnetics and superconductors.Comment: 12 pages, 5 figure

Two-pulse stimulated echo in magnets

The results of experimental study of two-pulse stimulated echo in ferromagnets of two types are presented. Ferromagnet Co and half-metal Co MnSi 2, in which a single-pulse echo formed by the distortion mechanism of the fronts of exciting pulse is also observed, are classified among the first type. Lithium ferrite and intermetal compound MnSb characterized by the absence of single-pulse echo in them - belong to the second type. For signals of two-pulse stimulated echo in the materials of the first type a short time and a long time of relaxations are observed. The short time is about the order of value shorter less than the spin-spin relaxation time. The long time is close to the transverse relaxation time of single-pulse echo formed by the distortion mechanism. The mechanisms that provide the possible interpretations of the peculiarities of the processes of nuclear magnetic relaxation are discussed.Comment: 10 pages, 7 figure

Oscillatory free induction decay in angular distribution of nuclear radiation

A theoretical consideration of the free induction decay (FID) signal formation in the angular distribution of radiation, emitted by oriented nuclei after excitation by a long radiofrequency resonance pulse tp ≫ T* 2, is carried out. The well-known theorem on the oscillatory FID signal is expanded for the case of second rank tensors. © 1984

On the theory of multipulsed excitation of spin-echo and free-induction decay signals in angular distribution of oriented nuclei radiation

A theoretical study of the effects of multipulsed NMR on the angular distribution of radiations from oriented nuclei is reported. The perturbation factors of the angular correlation function may be written in general form for any scheme of multipulsed excitation of a nuclear spin system. The irreversible relaxation is taken into account. The experimentally realized situations of spin-echo and free induction decay in angular distribution of nuclear radiation are considered. © 1985 J.C. Baltzer A.G., Scientific Publishing Company

Multiple-pulse NMR of oriented radioactive nuclei under electric-quadrupolar interactions

The formation of the nuclear spin echo in the Angular Distribution of Nuclear Radiations (ADNR) in the presence of combined magnetic-dipole and electricquadrupole interactions (EQI) is theoretically considered. The case of a perturbative EQI in addition to the dominant magnetic hyperfine interaction is analysed. When both interactions are extremely large, with the EQI much greater than the magnetic inhomogeniety, the excitation of spin-echo in ADNR by pulsed rf field, including transitions between a definite pair of quadrupole shifted Zeeman levels is considered. © 1990 J.C. Baltzer A.G., Scientific Publishing Company