63386 20190709135526.0 doi 10.1088/0953-2048/30/2/024003 sideral 97883 ART-2017-97883 eng Martinez-Pérez, M.J. NanoSQUID magnetometry of individual cobalt nanoparticles grown by focused electron beam induced deposition 2017 Access copy available to the general public Unrestricted We demonstrate the operation of low-noise nano superconducting quantum interference devices (SQUIDs) based on the high critical field and high critical temperature superconductor YBa2Cu3O7 (YBCO) as ultra-sensitive magnetometers for single magnetic nanoparticles (MNPs). The nanoSQUIDs exploit the Josephson behavior of YBCO grain boundaries and have been patterned by focused ion beam milling. This allows us to precisely define the lateral dimensions of the SQUIDs so as to achieve large magnetic coupling between the nanoloop and individual MNPs. By means of focused electron beam induced deposition, cobalt MNPs with a typical size of several tens of nm have been grown directly on the surface of the sensors with nanometric spatial resolution. Remarkably, the nanoSQUIDs are operative over extremely broad ranges of applied magnetic field (-1 T <µ0H <1 T) and temperature (0.3 K < 80 < K). All these features together have allowed us to perform magnetization measurements under different ambient conditions and to detect the magnetization reversal of individual Co MNPs with magnetic moments (1-30) × 106 µB. Depending on the dimensions and shape of the particles we have distinguished between two different magnetic states yielding different reversal mechanisms. The magnetization reversal is thermally activated over an energy barrier, which has been quantified for the (quasi) single-domain particles. Our measurements serve to show not only the high sensitivity achievable with YBCO nanoSQUIDs, but also demonstrate that these sensors are exceptional magnetometers for the investigation of the properties of individual nanomagnets. info:eu-repo/grantAgreement/EUR/FP6-COST/MP1201 info:eu-repo/semantics/openAccess All rights reserved http://www.europeana.eu/rights/rr-f/ 2.861 2017 PHYSICS, CONDENSED MATTER 23 / 67 = 0.343 2017 Q2 T2 PHYSICS, APPLIED 41 / 146 = 0.281 2017 Q2 T1 1.036 2017 Ceramics and Composites 2017 Q1 Condensed Matter Physics 2017 Q1 Metals and Alloys 2017 Q1 Materials Chemistry 2017 Q1 Electrical and Electronic Engineering 2017 Q1 info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion Müller, B. Schwebius, D. Korinski, D. Kleiner, R. (orcid)0000-0002-7742-9329 Sesé, J. Universidad de Zaragoza Koelle, D. 2003 395 Universidad de Zaragoza Dpto. Física Materia Condensa. Área Física Materia Condensada 30, 2 (2017), 024003 [10 pp.] Supercond. sci. technol. SUPERCONDUCTOR SCIENCE & TECHNOLOGY 0953-2048 1127891 http://zaguan.unizar.es/record/63386/files/texto_completo.pdf Postprint 134403 http://zaguan.unizar.es/record/63386/files/texto_completo.jpg?subformat=icon icon Postprint oai:zaguan.unizar.es:63386 articulos driver 2019-07-09-11:59:58 ARTICLE