Grain boundaries in granular materials-A fundamental limit for thermal stability
Applied Physics Letters
American Institute of Physics (AIP)
We show that thermal-stability and the associated switching field in well segregated, nanoscale granular materials is explained by grain boundary and interface effects. Grain boundaries pose a fundamental limit on scaling rooted in their chemical and morphological structure, while exchange interactions across interfaces cause the switching to deviate from the expected coherent Stoner-Wohlfarth behaviour. Measurements and simulations of CoCrPt-systems show a clear shift in applied field angle behaviour, arising from exchange-coupling between magnetic-phases, while the quantitative switching field can only be explained by a transition layer surrounding the grains. These results are potentially significant for Heat-Assisted-Magnetic Recording and Bit-Patterned-Media Recording. © 2013 AIP Publishing LLC.
We would like to thank the EPSRC for financial support under Grants No. EP/G032440/1, EP/G032300/1, the WWTF Project MA09-029 and the Royal Society.
This is the final version of the article. Available from the American Institute of Physics via the DOI in this record.
Vol. 102 (14), article 142402