The angular dependence of critical currents in Nb3Sn — Effect of some preparation conditions I. Experimental and structural investigations

The results of experimental investigations of the angular dependence of critical currents are presented. The samples studied have been prepared by chemical vapour deposition process in reaction atmosphere of different carrier and doping gases. The results have shown that such conditions influence greatly not only the absolute value of the critical current but also the ratioIc∥/Ic⊥ of the critical currents in magnetic fields parallel and perpendicular to the broad face of the tape. The microstructure studies show that the grain shape and size is changed appreciably when various carrier and doping gases are used.