Created by Digital Micrograph, Gatan Inc.


The next generation nano-magnetic devices for magnetic data storage raises  problems such as the reduction of grain size and ensuring of thermal stability of the written information. A major problem is that upon the decrease of ferromagnetic (FM) grain size, a limit is reached where the FM regions are no longer stable thermally, reaching the Superparamagnetic (SPM) limit. This is a serious problem, because in this state such particles can no longer be used in magnetic memories.

One of the possibilities of circumventing the SPM limit is by using the exchange bias that appears in hybrid ferromagnetic-antiferromagnetic (AFM) systems, but the lack of sufficient control of the nanostructure has limited effective applications in memories up to now. In addition, mechanisms for the enhancement of magnetic properties other than exchange bias have been proposed, such as interactions in FM nanostructures which can lead to collective states like superspin-glass or super FM states.

The present project proposes obtaining materials having improved magnetic properties for data storage in nanoelectronics, namely an increased thermal stability for FM nanoparticles (NPs), having the sizes imposed by the areal bit density required for the next generation devices (several nm). The materials studied are in the form of FM NPs in AFM or ferrimagnetic matrixes, or FM core/AFM or ferrimagnetic shell NPs in various thin film matrixes. The method used to obtain the FM/AFM systems is the pulsed laser deposition (PLD) method.

Our aim is to develop original FM/AFM nanostructures: new materials and combinations of FM core/AFM shells and/or matrixes, new NP morphologies and matrix crystalline structures, smaller NP sizes than those currently obtained. These have great potential for improved properties for magnetic memories: larger thermal stability (increased blocking temperatures) for NP dimensions of the order of nm. The optimized method for obtaining such structures will also be an end result of the research.



  Last update: 2.12.2014