Anomalous Peak in Microwave Surface Resistance Studies on Silver Doped Bi_1.84Pb_0.4Sr₂Ca_2.2Cu₃O₁₀ Superconductor

Abstract

We report surface resistance studies on silver (0 to 25 wt%) doped Bi_1.84Pb_0.4Sr₂Ca_2.2Cu₃O₁₀ samples prepared by spray drying technique. The XRD studies show the predominance of 2223 phase in the samples. The 10 wt% silver doped sample shows optimum superconducting characteristics viz, improved microstructure characteristics and the reduced resistive grain boundaries. Temperature dependent microwave surface resistance behaviour shows the apparence of two anomalous peaks (high temperature at T_c and low temperature near T_CI2) in samples when the Ag dopant level was increased beyond 10 Wt%.

Indexing terms:

• High temperature superconductor
• Microwave surface resistance

Additional information

Notes on contributors

G P Srivastava

Ganesh Prasad Srivastava was born in 1933. He obtained doctoral degree in microwave pressure broadening studies in 1957 from University of Allahabad. He pursued future research with Nobel Laureate Prof G Herzberg in National Research Council, Ottawa, Canada from 1960 to 1962 where he made significant contribution to the field of Microwave spectroscopy. He was the first to observe rotational transition in hydrogen bounded molecules. He also worked at the University of Sheffield (UK), University of Queensland (Australia), and University Piere-et-Marie Curie (France). In India he worked at different Universities and in 1974 he became Professor of Physics and in 1980, the Head of the department and the Dean of the Faculty of Science, Delhi University.

In his research careers he has to his credit over 195 research publications in international journals spanning the fields of spectroscopy, semiconductor physics magnetism, quantum electronics and microwave superconductivity. He has contributed to many international conferences. As an academician, he played a key role in introducing electronics courses into regular science academic programs all over the country for undergraduate course on computer science. He was the first Head of the Department of Electronics Science and the first Dean of the Faculty of Interdisciplinary and Applied Sciences in University of Delhi. The microwave community has been benefited by him both as an active researcher and as an educator.

He has organised many national as well as international conferences. He is one of the persons who is instrumental in establishing the Asia Pacific Microwave Conferences. At present he is actively leading a group working in the fields of high temperature superconducting microwave electronics in Delhi University.

Malay Ranjan Tripathy

Malay Ranjan Tripathy, was born in Orissa in 1969. He received his MSc Physics degree with Electronics as a special subject from Utkal University, Orissa. He has registered in the Department of Electronic Science, University of Delhi for his PhD degree. Recently he has submitted his thesis to the Univ of Delhi for the award of his PhD degree. For his PhD thesis, he has prepared high temperature BSCCO superconducting materials by solid state reaction, sol-gel and spray drying techniques. Besides the general characterization of materials (i.e. XRD, SEM, RT, Jc and AC susceptibility), he has developed his experimental setup for microwave studies. He has studied for the microwave absorption, microwave surface resistance and non-resonant microwave absorption of these high temperature superconductors. Currently he is interested in design and studies of superconducting resonators, filters and antennas.

Recently he has visited Intermag '99, May 18–21, 1999, at Kyongju, Korea and received a IEEE Magnetic Society student paper award. He has also visited FIM '99 at Stockholm, Sweden, August 12–15, 1999, to present an invited paper.

S K Bansal

S K Bansal, passed MSc Physics in 1966 from Agra University, Agra and obtained PhD degree from University of Delhi, Delhi in 1973 on the study of Electron Transport in Sb at low temperatures. Since 1973 working in Physics Department, Ramjas College, Delhi, teaching undergraduate students Physics of Materials and Semiconductor Devices. Besides teaching, he is involved in studies of High Power Pulsed Laser Interaction with amorphous and crystalline semiconductors, high T_c materials, microwave interaction with Ag doped BSCCO materials.