Reversible strain-induced magnetic phase transition in a van der Waals magnet

Mechanical deformation of a crystal can have a profound effect on its physical properties. Notably, even small modifications of bond geometry can completely change the size and sign of magnetic exchange interactions and thus the magnetic ground state. Here we report the strain tuning of the magnetic properties of the A-type layered antiferromagnetic semiconductor CrSBr achieved by designing a strain device that can apply continuous, in situ uniaxial tensile strain to two-dimensional materials, reaching several percent at cryogenic temperatures. Using this apparatus, we realize a reversible strain-induced antiferromagnetic-to-ferromagnetic phase transition at zero magnetic field and strain control of the out-of-plane spin-canting process. First-principles calculations reveal that the tuning of the in-plane lattice constant strongly modifies the interlayer magnetic exchange interaction, which changes sign at the critical strain. Our work creates new opportunities for harnessing the strain control of magnetism and other electronic states in low-dimensional materials and heterostructures.

Cardiovascular effects of experimentally induced efficacy (ability) appraisals at low and high levels of avoidant task demand

Subjects were led to believe they had low or high ability with respect to a scanning task and then given the chance to avoid a noise by attaining a low (easy) or high (difficult) standard on a version of the task. Performance period measurements indicated that heart rate reactivity was greater in the difficult than easy condition for high-ability subjects but greater in the easy than difficult condition for low-ability subjects. Furthermore, whereas heart rate responses tended to be greater for low- than for high-ability subjects when the standard was low, they were greater for high- than for low-ability subjects when the standard was high. Results for blood pressure reactivity were comparable, although pairwise comparisons were not as consistently reliable. The main findings conceptually replicate and extend effects from previous studies; they also call further into question conventional conceptions that intimate an inverse relation between perceived self-efficacy and physiologic responsivity in the face of threat.