Longitudinal magnetoresistance in YBa₂Cu₃O₇ at high magnetic fields up to 100 T

Abstract The investigation of transport characteristics in high-temperature superconductors under magnetic fields is one of the most important topics in condensed matter physics and transport applications. For YBa 2 Cu 3 O 7 (YBCO), the measurements of magnetoresistance (MR) under a high magnetic field are technically challenging because the required magnetic field ( B ) to suppress the superconductivity is 100 T class. The low temperature (from 52 to 150 K) longitudinal MR ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>B</mml:mi> <mml:mrow> <mml:mo>∥</mml:mo> </mml:mrow> </mml:mrow> </mml:math> ab -plane <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:mo>∥</mml:mo> </mml:mrow> <mml:mi>J</mml:mi> </mml:mrow> </mml:math> , where J is an electrical current) was measured up to 103 T in optimally doped YBCO thin films. A radio frequency reflection method and the single-turn coil technique were employed. The electrical resistivity ρ ab exhibited a non-saturating MR behavior until the highest field region, with the slope <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>β</mml:mi> <mml:mo stretchy="false">(</mml:mo> <mml:mrow> <mml:mo>=</mml:mo> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">d</mml:mi> </mml:mrow> <mml:mi>ρ</mml:mi> <mml:mrow> <mml:mo>/</mml:mo> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">d</mml:mi> </mml:mrow> <mml:mi>B</mml:mi> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> </mml:math> showing a pronounced deviation compared to the transverse MR ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>B</mml:mi> <mml:mrow> <mml:mo>∥</mml:mo> </mml:mrow> </mml:mrow> </mml:math> c -axis) case. These findings suggest a potential contribution due to the non-orbital origin in the high field phase of YBCO, because the quasiparticle orbital motion is expected to be absent in the longitudinal MR.