Instituto de Ciencia Molecular (ICMol), Universitat de València , Catedrático José Beltrán 2, E46980 Paterna, Spain.
ACS Nano. 2016 Feb 23;10(2):1764-70. doi: 10.1021/acsnano.5b06776. Epub 2016 Jan 13.
Imaging and manipulating the spin structure of nano- and mesoscale magnetic systems is a challenging topic in magnetism, yielding a wide range of spin phenomena such as skyrmions, hedgehog-like spin structures, or vortices. A key example has been provided by the vortex spin texture, which can be addressed in four independent states of magnetization, enabling the development of multibit magnetic storage media. Most of the works devoted to the study of the magnetization reversal mechanisms of the magnetic vortices have been focused on micrometer-size magnetic platelets. Here we report the experimental observation of the vortex state formation and annihilation in individual 25 nm molecular-based magnetic nanoparticles measured by low-temperature variable-field magnetic force microscopy. Interestingly, in these nanoparticles the switching of the vortex core can be induced with very small values of the applied static magnetic field.
对纳米和中尺度磁性系统的自旋结构进行成像和操控是磁性领域的一个具有挑战性的课题，它产生了广泛的自旋现象，如 skyrmions、类刺猬状的自旋结构或涡旋。一个关键的例子是涡旋自旋织构，它可以在磁化的四个独立状态中得到解决，从而实现多比特磁存储介质的发展。大多数致力于研究磁性涡旋磁化反转机制的工作都集中在微米级大小的磁性薄片上。在这里，我们通过低温变场磁强计显微镜实验观察到了在单个 25nm 分子基磁性纳米粒子中形成和湮灭的涡旋状态。有趣的是，在这些纳米粒子中，通过施加非常小的静态磁场就可以诱导涡旋核的切换。
