de Ory M C, Rollano V, Gomez A, Menghini M, Muñoz-Noval A, Gonzalez E M, Vicent J L
IMDEA-Nanociencia, Cantoblanco, 28049, Madrid, Spain.
Centro de Astrobiología (CSIC-INTA), Torrejón de Ardoz, 28850, Madrid, Spain.
Sci Rep. 2020 Jun 25;10(1):10370. doi: 10.1038/s41598-020-67317-7.
Little-Parks effect names the oscillations in the superconducting critical temperature as a function of the magnetic field. This effect is related to the geometry of the sample. In this work, we show that this effect can be enhanced and manipulated by the inclusion of magnetic nanostructures with perpendicular magnetization. These magnetic nanodots generate stray fields with enough strength to produce superconducting vortex-antivortex pairs. So that, the L-P effect deviation from the usual geometrical constrictions is due to the interplay between local magnetic stray fields and superconducting vortices. Moreover, we compare our results with a low-stray field sample (i.e. with the dots in magnetic vortex state) showing how the enhancement of the L-P effect can be explained by an increment of the effective size of the nanodots.
利特尔-帕克斯效应指的是超导临界温度随磁场变化的振荡现象。这种效应与样品的几何形状有关。在这项工作中，我们表明通过引入具有垂直磁化的磁性纳米结构，可以增强和操控这种效应。这些磁性纳米点产生的杂散场强度足以产生超导涡旋-反涡旋对。因此，利特尔-帕克斯效应偏离通常的几何约束是由于局部杂散磁场与超导涡旋之间的相互作用。此外，我们将我们的结果与一个低杂散场样品（即纳米点处于磁涡旋态的样品）进行比较，展示了利特尔-帕克斯效应的增强如何通过纳米点有效尺寸的增加来解释。
