Multilayer structure design with tunable magnetic properties
Magnetic thin films and the associated device components, such as the ones currently being employed in hard-drive disks (HDD) or MRAM memories, require magnetic materials with widely tunable properties to facilitate disruptive and novel technologies.
In our work, we have demonstrated how novel materials design on the nm length-scale can manipulate magnetic phase transitions. Specifically, we design and fabricate single-crystal CoRu alloy films with gradual changes in their Ru concentration. Such predefined gradual changes allow for controlling the occurrence of the second-order phase transition of ferromagnets at the Curie temperature Tc.
Similar materials design can be used to control multiple aspects of magnetic thin films, such as the thermodynamic critical exponents or their magnetization reversal and its temperature dependence.
References:
• “Temperature-Independent Coercivity in Compositionally Graded Ferromagnetic Multilayers”, M. Quintana et al., Physical Review Applied 18, 054024 (2022).
• “Modifying critical exponents of magnetic phase transitions via nanoscale materials design”, L. Fallarino et al., Physical Review Letters 127 (14), 147201 (2021).
• “Nanoscale control of temperature operation ranges for magnetocaloric applications”, J. S. Salcedo Gallo, A. Berger, M. Quintana, E. Restrepo Parra and L. Fallarino, J. Phys. D: Appl. Phys. 54, 304003 (2021).