PIER Photon Science Colloquium: Tailored nanomagnetism in exchange-coupled films: new surprises in an old system

by Kristiaan Temst (Instituut voor Kern- en Stralingsfysica, K.U.Leuven, Leuven, Belgium)

Friday, June 17, 2011 from to (Europe/Berlin)
at bldg. 28c, seminar room
When magnetic exchange coupling occurs at the interface between a ferromagnetic and an antiferromagnetic film, the material becomes magnetically harder and the magnetic hysteresis loop shifts along the field axis.  This peculiar phenomenon is called ‘exchange bias’ and, although it was discovered more than fifty years ago and is used widely in magnetic recording devices, the microscopic details of the interfacial coupling remain to be elucidated.  Using magnetoresistance measurements and polarized neutron reflectivity we have investigated the magnetic depth profile and the magnetic history in such ferromagnet/antiferromagnet layered systems, leading to a better understanding of the spin structure at the interface. Surprisingly, it was found that this interfacial spin structure can be manipulated, allowing to tailor the exchange bias effect.