Recent trends and perspectives of nanoSQUIDs: Introduction to 'Focus on nanoSQUIDs and their applications'

In recent years much effort has been devoted to the development of SQUIDs having a fl ux capture area less than 1 ? m 2 ( nanoSQUIDs ) , because they offer the possibility to investigate fascinating fi elds of physics. Since the first nanoSQUIDs were created, several nanoSQUID developments have been the subjects of many scienti fi c articles, special sessions at international conferences and special issues of scienti fi c journals. The present special issue reports advances in nanoSQUID design, fab- rication, performance and their applications including nanomagnetism, ultra-high spatial resolution magnetic microscopy and other intriguing topics of material science and condensed matter, and highlights the real potential of these quantum nanosensors. This preface brie fl y introduces the different nanoSQUID types, their performance and their main applications.