The influence of elevated magnetic fields on the texture formation of melt-processed Bi-2212

نویسندگان

  • E. Cecchetti
  • P. J. Ferreira
  • J. B. Vander Sande
چکیده

Ž . Melt-processing of BSCCO high-T superconductors HTS under an elevated magnetic field is an effective technique for c producing superconductors with enhanced critical current. This result is a consequence of the high degree of crystallographic texture achieved in the polycrystalline superconductor processed under a high magnetic field. Possible mechanisms for the orientation of Bi-2212 plate-like crystals under the influence of a magnetic field are analyzed, in particular, the orientation of Bi-2212 superconductor crystals during nucleation, crystal growth and grain growth. In order to understand the relevance of each of these mechanisms, the effect of an applied magnetic field during the different stages of the partial-melt process is studied. Experimental results confirm that most of the alignment is achieved in the early stages of crystal growth. q 2000 Elsevier Science B.V. All rights reserved.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Bi - 2212 r Ag tapes melt - grown under an elevated magnetic field ž / 0 – 10 T

Bi-2212rAg tapes with a thickness of 30 mm were melt-grown in elevated magnetic fields following two different thermal sequences. The transport critical current density, J dependence on the maximum processing temperature, cooling c rate, holding time and magnetic field was studied systematically. The quantity of impurity phase was decreased by reducing the holding time above the melting point o...

متن کامل

Preferred Orientation Contribution to the Anisotropic Normal State Resistivity in Superconducting Melt-Cast Processed Bi2Sr2CaCu2O8+δ

We describe how the contribution of crystallographic texture to the anisotropy of the resistivity of polycrystalline samples can be estimated by averaging over crystallographic orientations through a geometric mean approach. The calculation takes into account the orientation distribution refined from neutron diffraction data and literature values for the single crystal resistivity tensor. The e...

متن کامل

Role of internal gases and creep of Ag in controlling the critical current density of Ag-sheathed Bi2Sr2CaCu2Ox wires

High engineering critical current density JE of > 500A/mm 2 at 20T and 4.2K can be regularly achieved in Ag-sheathed multifilamentary Bi2Sr2CaCu2Ox (Bi-2212) round wire when the sample length is several centimeters. However, JE(20T) in Bi-2212 wires of several meters length, as well as longer pieces wound in coils, rarely exceeds 200A/mm. Moreover, long-length wires often exhibit signs of Bi-22...

متن کامل

J enhancement of Bi Sr CaCu O r Ag thick films melt - grownc 2 2 2 8 ž / under an elevated magnetic field 0 – 10 T

Ž . Ž . Superconductor films 25–125 mm thick were melt-grown under an elevated magnetic field 0–10 T . The degree of Ž . texture and transport critical current J of these films were enhanced by the application of a magnetic field. J increases c c with increasing magnetic field and the measured saturation magnetic field decreases with decreasing thickness of the film. This method provides for re...

متن کامل

TEM INVESTIGATION OF RAPIDLY SOLIDIFIED NDFEB HARD MAGNETIC MATERIAL

The surface condition and microstructure of near stoichiometric (Fe823Ndll.8B5.9) Nd-Fe-B alloy ribbons and the effect of melt spinning parameters were investigated using optical, scanning and transmission electron microscopes (SEM, TEM). The formation of gas pockets on the roll surface of the ribbons during melt spinning can prevent heat transform and result in local coarse grains. The local t...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2000