Unconventional GMR angular dependence using a compensated ferrimagnet

作者：Nam N T; Ranno L^*

来源：Journal of Magnetism and Magnetic Materials, 2010, 322(9-12): 1428-1430.

DOI：10.1016/j.jmmm.2009.07.007

• Ferrimagnetism
• Giant magnetoresistance
• Compensation temperature

We have designed a GdCo/Cu/NiFe giant magnetoresistance (GMR) trilayer , the magnetoresistance of which does not always depend on the angle between the magnetisations of the electrodes. Using a GdCo ferrimagnetic alloy close to compensation, it was possible to experimentally reach the spin flop field B-sf of the ferrimagnetic layer . Below B-sf, the ferrimagnetic layer behaves as a ferromagnetic layer , however above B-sf, the ferrimagnetic sublattice magnetisations are no longer antiparallel and rotate 90 degrees away from the GdCo layer totalmagnetisation, i.e. 90 degrees away from the applied field . the GMR responds to the angle between Co and NiFe magnetisations and not to the angle between GdCo and NiFe magnetisations. Such a structure allows to study the change of sign of the GdCo spin polarisation as a function of temperature, and details of the GdCo magnetisation when usual magnetometry is difficult. FeNi can be seen as a sensor for the in-plane component of Co sublattice magnetisation, whereas extraordinary Hall effect measurements give a complementary image of the perpendicular component of the Comagnetisation.

• 出版日期2010-6