Novel methods for the fabrication of ferromagnetic nickel and nickel boride thin films
Metal‐rich nickel boride thin films fabricated from boron‐containing precursor compounds by a cluster deposition process are shown to be ferromagnetic. The metal‐rich films fabricated by this approach exhibit hysteresis curves similar to those obtained for pure nickel foils. These films are a mixture of pure nickel and the Ni3B nickel boride phases. It is postulated that the hysteresis curves with smaller remnant magnetizations obtained from these films are a consequence of Ni3B inclusions within the films. Other novel organometallic source compounds for nickel chemical‐vapor deposition are briefly reviewed.
A Thermodynamic Estimation of the Chemical Vapor Deposition of Some Borides
Abstract The temperature dependencies of the change in Gibbs energy for a series of probable reactions of chemical vapor deposition (CVD) of TiB 2 , ZrB 2 , NbB 2 , TaB 2 , and LaB 6 using BCl 3 , BBr 3 , B 2 H 6 , B 5 H 9 , and B 10 H 14 as boron sources have been plotted on the basis of thermodynamic data from the literature. It has been shown that from a thermodynamic point of view the deposition of these borides should proceed in all cases under milder conditions when boron hydrides are the boron sources. Is has been established that of the two boron halides BBr 3 is the more suitable boron precursor in the CVD of the borides under consideration. Due to its properties this boron halide would probably prove especially appropriate for technological processes of transition metal diboride deposition.
Randi Weingarten, the American Federation of Teachers, and the Challenges of Policy Leadership in a Hostile Environment
Randi Weingarten is the president of the most vocal and influential teachers’ union, the American Federation of Teachers. Since rising through the ranks to AFT president in just two years, Weingarten is now a major, if not the most prominent, nongovernmental player in national education policy. She has earned deep respect from many educational policy actors. Likewise, Weingarten elicits withering criticism from others. This fascinating profile explains why, in such a brief period, she has proved to be a fierce, fearless, and effective leader under extraordinarily difficult circumstances. Her experience offers invaluable lessons applicable for others working in similarly intense policy arenas.