Switching ‘on’ the Luminescence of One Metal Ion with Another: Selectivity Characteristics with Respect to the Emitting and Triggering Metal

Complexes 1a·EuIII and 1b·EuIII, but not 1a·TbIII and 1b·TbIII, display strong ‘off–on’ switching of delayed luminescence with alkali cations; the switching efficiency of 1b·EuIII is stronger with K+ rather than Na+.

Local probing of ferroelectric and ferroelastic switching through stress-mediated piezoelectric spectroscopy

Strain effects have a significant role in mediating classic ferroelectric behavior such as polarization switching and domain wall dynamics. These effects are of critical relevance if the ferroelectric order parameter is coupled to strain and is therefore, also ferroelastic. Here, switching spectroscopy piezoresponse force microscopy (SS-PFM) is combined with control of applied tip pressure to exert direct control over the ferroelastic and ferroelectric switching events, a modality otherwise unattainable in traditional PFM. As a proof of concept, stress-mediated SS-PFM is applied toward the study of polarization switching events in a lead zirconate titanate thin film, with a composition near the morphotropic phase boundary with co-existing rhombohedral and tetragonal phases. Under increasing applied pressure, shape modification of local hysteresis loops is observed, consistent with a reduction in the ferroelastic domain variants under increased pressure. These experimental results are further validated by phase field simulations. The technique can be expanded to explore more complex electromechanical responses under applied local pressure, such as probing ferroelectric and ferroelastic piezoelectric nonlinearity as a function of applied pressure, and electro-chemo-mechanical response through electrochemical strain microscopy.

Starting slow: the effects of response-switching frequency on patterns of cardiovascular reactivity

Research findings suggest that switching between competing response sets can be resource demanding. The current study focused on concurrent health-relevant physiological effects of task switching by assessing cardiovascular response at varying levels of switch frequency. The participants performed a response-switching task at three different levels of response set switching frequency (low, medium and high) while measurements of blood pressure and heart rate were taken. One group was exposed to response-switching frequency conditions in the order low → medium → high, while the other group was exposed to the same task conditions in the reverse order (i.e. high → medium → low). The results showed that the participants in the low → medium → high switch frequency group recovered faster from initially heightened systolic blood pressure when compared with participants in the high → medium → low group. It is concluded that the results point to a physiological "carry over" effect associated with beginning a task at rapid response switching frequency levels, and suggest the importance of habituation to task demands as a means of offsetting potentially unhealthy levels of reactivity. Implications for modern work environments are discussed.