Vortex Softening: Origin of the Second Peak Effect in <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>Bi</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow><mrow><msub><mrow><mi>Sr</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow><mrow><msub><mrow><mi>CaCu</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow><mrow><msub><mrow><mi>O</mi></mrow><mrow><mn>8</mn><mo>+</mo><mi>δ</mi></mrow></msub></mrow></math></span>

V. F. Correa; G. Nieva; F. de la Cruz

doi:10.1103/PhysRevLett.87.057003

Vortex Softening: Origin of the Second Peak Effect in ${Bi}_{2} {Sr}_{2} {CaCu}_{2} O_{8 + δ}$

V. F. Correa, G. Nieva, and F. de la Cruz

Phys. Rev. Lett. 87, 057003 – Published 13 July 2001

Abstract

Magnetic hysteresis and transverse ac permeability measurements in ${Bi}_{2} {Sr}_{2} {CaCu}_{2} O_{8 + δ}$ allow a comparative analysis of the critical current with the elastic response of vortex structures, in equilibrium with their pinning potential, in the field and temperature region where the second peak is detected. This study provides strong evidence that the second peak has its origin in changes of the elastic equilibrium properties of the vortex structures.