Comparison of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>J</mml:mi> <mml:mtext>c</mml:mtext> </mml:msub> </mml:mrow> </mml:math> measurements obtained by magnetisation and transport methods for a GdBCO-Ag

Abstract Accurate numerical modelling of bulk rare-earth barium cuprate ((RE)BCO) high-temperature superconductors requires measured data of the temperature and magnetic field dependence of the critical current density, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>J</mml:mi> <mml:mtext>c</mml:mtext> </mml:msub> </mml:mrow> </mml:math> , and flux-flow exponent, n . However, there is limited published <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>J</mml:mi> <mml:mtext>c</mml:mtext> </mml:msub> </mml:mrow> </mml:math> and n data for modern (RE)BCO bulks. In this work, transport and magnetisation methods were applied to characterise <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>J</mml:mi> <mml:mtext>c</mml:mtext> </mml:msub> </mml:mrow> </mml:math> , n , and the critical temperature, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>T</mml:mi> <mml:mtext>c</mml:mtext> </mml:msub> </mml:mrow> </mml:math> , of a commercially available top-seeded melt growth (TSMG) GdBCO-Ag bulk. Both measurement methods exhibit good quantitative and qualitative agreement when the transport electric field criterion is scaled from 1 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mtext>μ</mml:mtext> <mml:mrow> <mml:mi mathvariant="normal">V</mml:mi> </mml:mrow> <mml:mstyle scriptlevel="0"/> <mml:msup> <mml:mrow> <mml:mi>cm</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> to 10 −4 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mtext>μ</mml:mtext> <mml:mrow> <mml:mi mathvariant="normal">V</mml:mi> </mml:mrow> <mml:mstyle scriptlevel="0"/> <mml:msup> <mml:mrow> <mml:mi>cm</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> . Transport-derived thermo-magneto-angular dependent <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>J</mml:mi> <mml:mtext>c</mml:mtext> </mml:msub> </mml:mrow> </mml:math> data for the TSMG GdBCO-Ag bulk are compared to equivalent data for a SuNAM SCN12700 GdBCO coated-conductor tape. Significant qualitative differences are observed between the data for the bulk and tape, with the tape data featuring neither a fishtail effect nor a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>B</mml:mi> <mml:mo>∥</mml:mo> <mml:mi>c</mml:mi> </mml:mrow> </mml:math> peak, both of which are present in the bulk data. A reliable sample preparation and mounting method is presented, which enables the transport characterisation of (RE)BCO bulk superconductors over a large range of temperatures and applied field magnitudes and angles. All <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>J</mml:mi> <mml:mtext>c</mml:mtext> </mml:msub> </mml:mrow> </mml:math> and n data presented within this manuscript are available in the supplementary material , and can be interpolated into finite-element models to more accurately capture the superconducting behaviour of GdBCO superconductors.