Identification of novel compositions of ferromagnetic shape-memory alloys using composition spreads.

Exploration of new ferroic (ferroelectric, ferromagnetic or ferroelastic) materials continues to be a central theme in condensed matter physics and to drive advances in key areas of technology. Here, using thin-film composition spreads, we have mapped the functional phase diagram of the Ni-Mn-Ga system whose Heusler composition Ni(2)MnGa is a well known ferromagnetic shape-memory alloy. A characterization technique that allows detection of martensitic transitions by visual inspection was combined with quantitative magnetization mapping using scanning SQUID (superconducting quantum interference device) microscopy. We find that a large, previously unexplored region outside the Heusler composition contains reversible martensites that are also ferromagnetic. A clear relationship between magnetization and the martensitic transition temperature is observed, revealing a strong thermodynamical coupling between magnetism and martensitic instability across a large fraction of the phase diagram.

Ethical issues in psychological assessment in school settings.

It is especially important for psychologists providing assessment and testing services in schools to be able to recognize and negotiate the ethical challenges specific to academic settings. In this article I address ethical issues in the areas of informed consent, nondiscriminatory assessment, projective personality assessment, and computerized psychological testing. One of the most frequent ethical issues that confronts psychologists in the schools is the process of parental consent and involvement. Psychologists are also obligated to select nonbiased test instruments and use them in a way that is not racially or culturally biased. There are several factors to consider when using projective testing in a school setting, and the use of computerized psychological assessment measures raises significant ethical issues. Although concrete solutions are not always available for these complex situations, a basis for ethical decision making is presented.

Optical and nonlinear optical study of KTa(0.52) Nb(0.48) O(3) epitaxial film.

The second-order nonlinear optical coefficients d(33) , d(31) , and d(15) of KTa(0.52) Nb(0.48) O(3) epitaxial thin films grown upon MgO were studied by the standard Maker fringe method of an anisotropic medium. The measured d(33)=-84pm/V is 2.8 times the d(33) of LiNbO(3). The refractive indices n(e) and n(o) at several wavelengths were determined by TE and TM waveguide mode measurements. The data presented here point out the excellent qualities of KTa(1-x) Nb(x)O (3) films for use in integrated optics applications.