964 research outputs found

    Electromagnetically induced transparency in cold 85Rb atoms trapped in the ground hyperfine F = 2 state

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    We report electromagnetically induced transparency (EIT) in cold 85Rb atoms, trapped in the lower hyperfine level F = 2, of the ground state 52S1/2^{2}S_{1/2} (Tiwari V B \textit{et al} 2008 {\it Phys. Rev.} A {\bf 78} 063421). Two steady state Λ\Lambda-type systems of hyperfine energy levels are investigated using probe transitions into the levels Fâ€Č^{\prime} = 2 and Fâ€Č^{\prime} = 3 of the excited state 52P3/2^{2}P_{3/2} in the presence of coupling transitions F = 3 →\to Fâ€Č^{\prime} = 2 and F = 3 →\to Fâ€Č^{\prime} = 3, respectively. The effects of uncoupled magnetic sublevel transitions and coupling field's Rabi frequency on the EIT signal from these systems are studied using a simple theoretical model.Comment: 12 pages, 7 figure

    Dynamics of iron atoms across the pressure-induced Invar transition in Pd_3Fe

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    The ^(57)Fe phonon partial density of states (PDOS) in L1_2-ordered Pd_3Fe was studied at high pressures by nuclear resonant inelastic x-ray scattering (NRIXS) measurements and density functional theory (DFT) calculations. The NRIXS spectra showed that the stiffening of the ^(57)Fe PDOS with decreasing volume was slower from 12 to 24 GPa owing to the pressure-induced Invar transition in Pd_3Fe, with a change from a high-moment ferromagnetic (FM) state to a low-moment (LM) state observed by nuclear forward scattering. Force constants obtained from fitting to a Born–von Kármán model showed a relative softening of the first-nearest-neighbor (1NN) Fe-Pd longitudinal force constants at the magnetic transition. For the FM low-pressure state, the DFT calculations gave a PDOS and 1NN longitudinal force constants in good agreement with experiment, but discrepancies for the high-pressure LM state suggest the presence of short-range magnetic order

    Magnetic susceptibility of EuTe/PbTe Heisenberg superlattices: experimental and theoretical studies

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    We report results on the temperature dependence of the susceptibilities of a set of MBE-grown short-period EuTe/PbTe antiferromagnetic superlattices having different EuTe layer thicknesses. In-plane and orthogonal susceptibilities have been measured and display a strong anisotropy at low temperature, confirming the occurrence of a magnetic phase transition in the thicker samples, as seen also in neutron diffraction studies. We suggest that dipolar interactions stabilize antiferromagnetic long-range order in an otherwise isotropic system and we present numerical and analytical results for the low-temperature orthogonal susceptibility.Comment: 30 pages, 8 ps figures, RevTe

    Self‐compassion, self‐ forgiveness, suicidal ideation and self‐harm: a systematic review

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    Self‐compassion has been implicated in the aetiology and course of mental health with evidence suggesting an association between greater self‐compassion and lower emotional distress. However, our understanding of the nature and extent of the relationship between self‐compassion and self‐harm (self‐injury regardless of suicidal intent) or suicidal ideation remains unclear. This review, therefore, aimed to critically evaluate the extant literature investigating this relationship. To do so, a systematic search, including terms synonymous with self‐compassion, was conducted on three main psychological and medical databases (Web of Science, PsycINFO and Medline). Only studies investigating self‐compassion or self‐forgiveness and self‐harm or suicidal ideation were found to be relevant to the review. 18 studies were included in the final narrative synthesis. Heterogeneity of studies was high and the majority of studies were quantitative and cross‐sectional (n=16) in design. All studies reported significant associations between higher levels of self‐forgiveness or self‐compassion and lower levels of self‐harm or suicidal ideation. Several studies suggested that self‐compassion or self‐forgiveness may weaken the relationship between negative life events and self‐harm. In conclusion, this review highlights the potential importance of self‐compassion in the aetiology of suicidal thoughts and self‐harm. We discuss the clinical and research implications

    Magnetic properties of pure and Gd doped EuO probed by NMR

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    An Eu NMR study in the ferromagnetic phase of pure and Gd doped EuO was performed. A complete description of the NMR lineshape of pure EuO allowed for the influence of doping EuO with Gd impurities to be highlighted. The presence of a temperature dependent static magnetic inhomogeneity in Gd doped EuO was demonstrated by studying the temperature dependence of the lineshapes. The results suggest that the inhomogeneity in 0.6% Gd doped EuO is linked to colossal magnetoresistance. The measurement of the spin-lattice relaxation times as a function of temperature led to the determination of the value of the exchange integral J as a function of Gd doping. It was found that J is temperature independent and spatially homogeneous for all the samples and that its value increases abruptly with increasing Gd doping.Comment: 14 pages, 10 figures, to be published in Physical Review
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