Spin-strain coupling in NiCl2-4SC(NH2)2

We report results of ultrasonic investigations of the quantum S = 1 spin-chain magnet NiCl2-4SC(NH2)2, also known as DTN, in magnetic fields up to 18 T and temperatures down to 0.3 K. A field H along the [001] direction induces a transition into an antiferromagnetic phase with T(N)max ≈ 1.2 K. Accordingly, at T = 0 there are two quantum critical points at ~2.1 T and at ~12.6 T. The acoustic c33 mode, propagating along the spin chains, shows a pronounced softening close to the phase transition, accompanied by energy dissipation of the sound wave. The H-T phase diagram obtained from our measurements is compared with results from other experimental investigations and the low-temperature acoustic anomalies are traced up to T > T(N). We also report frequency-dependent effects, which open the possibility to investigate the spin fluctuations in the critical regions. Our observations show an important role of the spin-phonon coupling in DTN

Character of magnetic excitations in a quasi-one-dimensional antiferromagnet near the quantum critical points: Impact on magneto-acoustic properties

We report results of magneto-acoustic studies in the quantum spin-chain magnet NiCl$_2$-4SC(NH$_2$)$_2$ (DTN) having a field-induced ordered antiferromagnetic (AF) phase. In the vicinity of the quantum critical points (QCPs) the acoustic $c_{33}$ mode manifests a pronounced softening accompanied by energy dissipation of the sound wave. The acoustic anomalies are traced up to $T > T_N$, where the thermodynamic properties are determined by fermionic magnetic excitations, the "hallmark" of one-dimensional (1D) spin chains. On the other hand, as established in earlier studies, the AF phase in DTN is governed by bosonic magnetic excitations. Our results suggest the presence of a crossover from a 1D fermionic to a 3D bosonic character of the magnetic excitations in DTN in the vicinity of the QCPs.Comment: 5 pages, 4 figures. Accepted for publication by Phys. Rev

Does Light Quality Influence Arabidopsis thaliana Growth in Controlled Environments?

This study examines the use of diverse lamp types, with inherently different spectral attributes, to determine light quality influence on Arabidopsis thaliana growth in controlled environments

We Don’t Always Mean What We Say: Attitudes Toward Statutory Exclusion of Juvenile Offenders From Juvenile Court Jurisdiction

In the United States, juvenile offenders are often excluded from the jurisdiction of the juvenile court on the basis of age and crime type alone. Data from national surveys and data from psycholegal research on support for adult sanction of juvenile offenders are often at odds. The ways in which questions are asked and the level of detail provided to respondents and research participants may influence expressed opinions. Respondents may also be more likely to agree with harsh sanctions when they have fewer offender- and case-specific details to consider. Here, we test the hypothesis that attitudes supporting statutory exclusion laws measured in the absence of specific case-specific details may not be the best indicator of agreement with such laws in practice. We found that support for statutory exclusion was affected by exposure to information about an offender’s unique situation and by exposure to general scientific information about adolescent development. These results suggest that despite an apparent widespread agreement with automatic exclusion statutes, laypersons consider factors other than those allowed by the law when they are asked how to treat an individual offender