Abstract
Tunnelling characteristics have been measured forCo-insulator-Py magnetic junctions with Dy- or Gd-dopedAl2O3 barriers. The theoretically predicted enhancement ofthe magneto-resistance due to resonant tunnelling in the presenceof paramagnetic impurities is not borne out. However, even afull monolayer of Dy or Gd has no detrimental effect on thejunction magneto-resistance (JMR) at low temperature and lowbias voltage. With increasing temperature and bias, the JMR ofthe doped junctions decreases significantly faster than the JMRof the Al2O3 control junctions. Junctions in which theentire barrier has been replaced by Dy2O3 or Gd2O3show strong non-linear current-voltage characteristics, butdisplay no JMR. It is shown that not direct tunnelling butspin-independent impurity-assisted tunnelling is the primaryconductance channel in these junctions.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
