{'fraction_non_alphanumeric': 0.018856447688564478, 'fraction_numerical': 0.0072992700729927005, 'mean_word_length': 5.302681992337165, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
A DIFFERENT SPIN ON NANOPARTICLE MAGNETIC VORTEX CORES

Magnetic vortices are an in-plane closed-flux magnetization characterized by either clockwise or counterclockwise rotation and a nanometric-size central spot called a vortex core, which has out-of-plane magnetization pointing either up or down. These phenomena could eventually be harnessed for novel nonvolatile data storage or other spintronic applications. However, to reach this goal, researchers must learn not only how to stabilize the magnetic vortex state but also how to control the formation and switching of the vortex core. Both imaging and manipulating the spin structure of nanoand mesoscale magnetic systems has remained a challenge, thwarting further advances. In a new study, Pinilla-Cienfuegos et al. (DOI: 10.1021/ acsnano.5b06776) developed a system enabling observation and manipulation of the vortex core in nanoparticles, permitting them to witness and to control vortex state formation and annihilation. Their system relied on magnetically soft nanoparticles from the Prussian blue family. After dispersing these cubic nanoparticles in water and depositing them by simple drop casting on a silicon substrate, the researchers used magnetic force microscopy at low temperature and low pressure to image the vortex core. Their low-noise images show full reversal of the vortex core between down and up states at small values of the applied magnetic field. The authors suggest that these findings open the possibility of using the polarization of individual magnetic nanoparticles’ vortex cores as bits of memory for the development of multibit magnetic storage media.