Spin pumping from permalloy into uncompensated antiferromagnetic Co doped zinc oxide
Sprache des Titels:
Englisch
Original Kurzfassung:
Heterostructures of Co-doped ZnO and Permalloy were investigated for their static and dynamic magnetic interactions. The highly
Co-doped ZnO is paramagnetic at room temperature and becomes an uncompensated antiferromagnet at low temperatures, showing a
narrowly opened hysteresis and a vertical exchange-bias shift even in the absence of any ferromagnetic layer. At low temperatures in
combination with Permalloy, an exchange bias is found causing a horizontal as well as a vertical shift of the hysteresis of the heterostructure
together with an increase in coercive field. Furthermore, an increase in the Gilbert damping parameter at room temperature
was found by multifrequency ferromagnetic resonance (FMR), indicating spin pumping. Temperature dependent FMR shows a
maximum in magnetic damping close to the magnetic phase transition. These measurements also evidence the exchange-bias interaction
of Permalloy and long-range ordered Co?O?Co structures in ZnO, which are barely detectable by SQUID due to the shorter
probing times in FMR.
Forschungs-