Search for high temperature memory effects in magnetic nanoparticles

Nanoparticle materials have become a promising candidate for a new kind of storage media based on thermally induced memory effects due to the possibility to tailor their magnetic properties and behaviour. In this study, we have investigated whether the magnetic memory effects could appear at high, industry accessible temperatures including the possibility of thermal data inscription. Investigated iron oxide nanoparticles were synthesized by poliol method, which has been modified in order to allow control of particle agglomeration and consequently magnetic properties. Structure, morphology and the degree of nanoparticle agglomeration were studied by X-Ray diffraction, Transmission Electron Microscopy and Dynamic Light Scattering techniques, while magnetic properties as well as memory effects were measured on a commercial SQUID-based magnetometer. Results of the study confirmed that in super spin glass magnetite nanoparticles, magnetic memory effects can be observed up to 200 K which represents much higher temperatures in comparison to those achieved in spin glasses and other glassy materials. Procedures of writing and reading (inscribing and retrieving) of digital information in such a material were demonstrated and discussed in details. (C) 2020 Elsevier B.V. All rights reserved.