posted on 2016-01-08, 00:00authored byElena Pinilla-Cienfuegos, Samuel Mañas-Valero, Alicia Forment-Aliaga, Eugenio Coronado
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.