Dielectric
measurements on formamidinium lead halide perovskites,
FAPbCl3 and FAPbBr3, compared to those of MAPbCl3 and previously reported MAPbBr3, reveal the strongly
suppressed temperature dependence of dielectric constants in FA compounds
in the temperature range of approximately 140–300 K. Although
the behavior of dielectric constants of FA compounds for temperatures
<140 K resembles that of the MAPbX3 system, the absence
of any strong temperature dependence in sharp contrast to MA analogues
in the higher temperature range up to room temperature suggests that
the formamidinium (FA) dipoles are in a deep-frozen glassy state unlike
the MA dipoles that rotate nearly freely in the temperature range
relevant for any photovoltaic application. This observation is further
supported by the temperature-dependent single-crystal X-ray diffraction
(XRD) results.
We present a combination of thermodynamic and dynamic experimental signatures of a disorder driven dynamic cooperative paramagnet in a 50% site diluted triangular lattice spin-1 2 system: Y 2 CuTiO 6. Magnetic ordering and spin freezing are absent down to 50 mK, far below the Curie-Weiss scale ð−θ CW Þ of ∼134 K. We observe scaling collapses of the magnetic field and temperature dependent magnetic heat capacity and magnetization data, respectively, in conformity with expectations from the random singlet physics. Our experiments establish the suppression of any freezing scale, if at all present, by more than 3 orders of magnitude, opening a plethora of interesting possibilities such as disorder stabilized long range quantum entangled ground states.
It is believed that ferroelectrics may serve as efficient photocatalysts as well as photovoltaic materials but for their large bandgaps which does not allow them to absorb a large part of the solar spectrum. We have explored theoretically within ab-initio density functional theory-based calculations, the efficacy of Cu and Te to co-dope BaTiO3 in reducing its bandgap while retaining its ferroelectric properties. Examining a dopant concentration of 11%, we find an insulating ground state being realized with a band gap reduction of 0.42 eV from the value for undoped BaTiO3 for some doping configurations. Ferroelectric distortions are found to survive even in the presence of doping suggesting possible applications in photocatalysis as well as photovoltaics.
In Bangladesh, iron deficiency is the most common cause of anemia and remains a significant public health concern. Being a high anemia prevalent country, numerous efforts have been made to confront the issue especially among women and children by both local and international actors. Though the situation has substantially improved in recent years, a staggering number of adult women are currently living with anemia. The etiology of anemia is a multifactorial problem and has been proposed to be associated with various household, societal, economic, cultural factors apart from dietary habits. However, evidence regarding the household arrangements and socioeconomic determinants of anemia is scarce, especially in the context of Bangladesh. To this end, we utilized the 2011 demographic and health survey data to explore the association between anemia status and selected demographic, socioeconomic, and household characteristics. Our result showed significant correlation of anemia with both sociodemographic and household characteristics. Among the sociodemographic variables the following were found to be significantly associated with anemia status: age (p = 0.014; OR = 1.195; 95% CI = 1.036–1.378) and microcredit membership (p = 0.014; OR = 1.19; 95% CI = 1.037–1.386). Regarding the household arrangements, women utilizing biomass fuel for cooking (p < 0.019; OR = 1.82; 95% CI = 0.981–2.460) were more likely to be anemic.
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