Exchange bias in epitaxial and polycrystalline thin film Ru2MnGe/Fe bilayers

Balluff J, Meinert M, Schmalhorst J-M, Reiss G, Arenholz E. Exchange bias in epitaxial and polycrystalline thin film Ru2MnGe/Fe bilayers. Journal of Applied Physics. 2015;118(24): 243907.We report on thin film bilayers of the antiferromagnetic Heusler compound Ru2MnGe and Fe, as well as the resulting exchange bias field at low temperatures and its temperature dependence. Epitaxial Ru2MnGe/Fe bilayers show an exchange bias field up to 680Oe at 3K. For increasing temperatures, a linearly decreasing exchange bias field is found, which vanishes at 130K. Furthermore, we grew polycrystalline Ru2MnGe showing an exchange bias field up to 540 Oe, which vanishes around 30K. By adding a very thin intermediate layer of Mn, the exchange bias field for polycrystalline samples has been increased by about 40%. We discuss differences between the epitaxial and polycrystalline films regarding magnetic and crystallographic properties and compare our results to already published work on this system. (C) 2015 AIP Publishing LLC