Magnetic measurements of the upper critical field of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi mathvariant="normal">YBa</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi mathvariant="normal">Cu</mi></mrow><mrow><mn>3</mn></mrow></msub></mrow></math><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi mathvariant="normal">O</mi></mrow><mrow><mn>7</mn><mi mathvariant="normal">−</mi><mi mathvariant="normal">δ</mi></mrow></msub></mrow></math> single crystals

U. Welp; W. K. Kwok; G. W. Crabtree; K. G. Vandervoort; J. Z. Liu

doi:10.1103/PhysRevLett.62.1908

Magnetic measurements of the upper critical field of ${YBa}_{2}$ ${Cu}_{3}$ $O_{7 - δ}$ single crystals

U. Welp, W. K. Kwok, G. W. Crabtree, K. G. Vandervoort, and J. Z. Liu

Phys. Rev. Lett. 62, 1908 – Published 17 April 1989

Abstract

dc magnetization measurements in fields up to 5 T on single crystals of ${YBa}_{2}$ ${Cu}_{3}$ $O_{7 - δ}$ reveal a well defined onset of diamagnetism allowing a unique magnetic determination of the upper critical field and its anisotropy. The upper-critical-field slopes are -1.9 and -10.5 T/K corresponding to coherence lengths of 16 and 3 Å for fields perpendicular and parallel to the CuO planes. At the magnetically determined nucleation temperatures no distinct features are found in resistive transition curves.