AC losses in a commercial Bi:2223/Ag tape

Abstract

We have investigated the effect of temperature, field amplitude, frequency and orientation of the field on AC losses in a commercial Bi:2223/Ag tape. The measurements were performed using an AC susceptometer. The experimental results show that the losses depend on field amplitude, temperature, and strongly on frequency. Due to the strong dependence of AC losses on frequency, measurements were pursued at several frequencies between 20 Hz and 10 kHz, at both 20 and 30 K. The strong frequency dependence at these low temperatures is attributed to eddy current losses or/and inter-filamentary coupling losses. At higher temperatures and low frequencies, the main contribution to AC losses comes from hysteresis losses due to the flux entry into and exit from the superconducting tape during the up and down swings of the magnetic field. We have calculated the hysteresis losses in the critical state framework, as a function of AC field amplitudes and temperature, for planar geometry. Experimental data are analyzed by comparing them with the calculated curves.

AC losses in superconductors shielded by a normal metal or another superconductor

“…The losses per cycle therefore decrease weaker at higher frequencies. Some measurements indicate this [21][22][23][24][25][26]. Our results are obtained by the analogy with the induced currents in normal metals.…”

AC loss study by AC susceptibility measurement in a commercial Bi:2223/Ag tape prepared by the CTFF method: H \parallel c axis and short specimen

“…Exploration of the parameters playing roles in the loss mechanisms can be useful in determining the optimum operating conditions. Recently, extensive studies have been done to analyze the parameters playing the role of the AC losses of BSCCO/Ag tapes [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. For a monofilament tape, the AC loss is composed of the hysteretic loss in the superconducting core and the eddy current loss in the silver.…”

Effect of dc field on ac-loss peak in a commercial Bi:2223/Ag tape

“…The fitting parameters of H *m0 = 110 Oe, n = 0.25, p = 2.2, T cm = 108 K gives quite good results to compare the experimental and calculated curves. Since we have kept the frequency fixed at low enough value (20 Hz), we neglected the contribution of eddy current and coupling loss here which is discussed in references [23,24]. TUBITAK-TBAG is gratefully knowledge for supporting the current study under grant contract no.…”

“…In addition, many researchers have studied analyzing the parameters playing the role of the ac losses of BSCCO/ Ag tapes [14][15][16][17][18][19][20][21][22][23][24]. Exploration of the parameters playing roles in the loss mechanisms can be useful in order to determine the optimum operating conditions.…”

“…Exploration of the parameters playing roles in the loss mechanisms can be useful in order to determine the optimum operating conditions. Çelebi et al have investigated the effect of frequency, field amplitude, and orientation of the field (namely parallel [23] and perpendicular [24] to the wide face of the tape) on ac losses in a commercial Bi:2223/Ag tape.…”