Motohide Matsuda

Effect of annealing on properties of bismuth based highTc superconductors

A novel method to increase the amount of the 110 K phase in the Bi-Sr-Ca-Cu-O system was examined. After the sample with composition of Bi2Sr2CaCu2Ox had been calcined, it was soaked in ethanol containing copper acetate and calcium acetate, the amounts of which were determined to give the composition of Bi2Sr2Ca2Cu3Oy after sintering. Subsequently, annealing at about 400 °C was conducted to examine the stability of the 110 K phase. The sample containing mainly the 80 K phase and a small amount of the 110 K phase showed an increase in the amount of the 110 K phase while that containing only the 80 K phase showed no change. Therefore, it is presumed that the 110 K phase may grow when the excess calcium and copper coexist adjacent to the 80 K phase at relatively low temperatures such as 400 °C.

Fabrication of Bi-Sr-Ca-Cu-O Superconductor From Nitrate Solutions

Abstract The Bi-based superconductor was fabricated employing the nitrate solution method. The phase development and super conducting property were examined by changing the composition and heat-treatment conditions. The optimal nominal composition was found to be Bi/Sr/Ca/Cu=2/2/2/3.5 with Tc(0)=54.5K.

EVALUATION METHODS FOR PROPERTIES OF NANOSTRUCTURED BODY

Publisher Summary The functions inherent in nanoparticles can be maintained while lowering their reactivity by fabricating nanoparticles into nanostructures. Stable nanostructured materials, fully utilizing the functions of nanoparticles, can be created by fabricating composite and bulk materials from nanoparticles, depending on their intended use. This chapter deals with such nanostructured materials and their various functions and the characteristic evaluation by function. It summarizes the nature of nanostructures, relevant examples of the relations between nanostructures and their characteristics, and the functionality and the evaluation of the characteristics of nanostructures. The chapter describes an electrode of a solid oxide fuel cell (SOFC), the structure of which is controlled using surface-coating type composite particles and the inner-dispersion type composite particles, as an example to explain the relation between nanostructures and their functional performance. In fabricating nanostructures in the application of nanoparticles, new functionalities are expected to produce many applications ranging over almost all fields in the coming years, with the advancement of technology. The chapter discusses the functional characteristics that are expected to be implemented in nanostructures in the coming future, including mechanical characteristics, thermal characteristics, electrical characteristics, electrochemical characteristics, electromagnetic characteristics, optical characteristics, catalytic characteristics, and gas permeability and separation characteristics.