Northern Illinois University

About: Northern Illinois University is a education organization based out in DeKalb, Illinois, United States. It is known for research contribution in the topics: Large Hadron Collider & Population. The organization has 8818 authors who have published 20008 publications receiving 632341 citations. The organization is also known as: NIU.

Structure-properties phase diagram for La 1 − x Sr x MnO 3 ( 0.1 x 0 . 2 )

Abstract: By combining the results of magnetization, resistivity, and neutron powder-diffraction data for stoichiometric ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{MnO}}_{3},$ we have constructed a phase diagram that describes the magnetic, transport, and structural properties and the relationships among them as a function of composition $(0.1l~xl~0.2)$ and temperature (10--340 K). We show that, with increasing Sr content, the Curie temperature increases linearly, while the temperature of an orbital ordering transition to a state with a large coherent Jahn-Teller (JT) distortion decreases. These two phase-transition lines cross at $x=0.145$ and $T=210\mathrm{K}.$ When the transition to the ferromagnetic state occurs in a phase that has a large coherent JT distortion $(xl0.145),$ a strong magnetolattice coupling is observed; the coherent JT distortion is dramatically reduced and the incoherent distortion is enhanced in the ferromagnetic phase. For $xg0.145,$ where the coherent JT distortion is small above Curie temperature, magnetolattice coupling reduces the incoherent distortion at ${T}_{C}$ and strongly suppresses the transition to a phase with a large coherent JT distortion. These observations are consistent with a competition between ferromagnetism and JT distortion that is mediated by a colossal spin-charge-lattice coupling. A metallic state occurs below the Curie temperature when both coherent and incoherent JT distortions are suppressed.

Adolescent Processing of Social and Physical Threat Communications

Abstract: Using the predictions of the ordered protection motivation model (OPM), the authors examined 371 adolescents' reactions to physical and social threat appeals in drug prevention public service announcements. Sensation seeking was also included in the experiment and analysis. In support of the notion that the social implications of a response to a threat message influence the message's effectiveness, social threat communications were more persuasive than physical threat communications. Sensation seeking emerged as an important variable moderating response to threat communications, supporting the argument that responses may be due to factors other than the communication itself. In contrast to the argument that fear arousal is a prerequisite for effective response to threat messages, the authors found fear arousal unnecessary for persuasion to occur. The implications of the findings for the effectiveness of public service announcements are discussed.