Giant magnetoresistance effect of Co-TbN macroscopic ferrimagnets

Abstract

A new macroscopic ferrimagnet Co-TbN has TbN precipitates in a Co matrix. The Co-TbN system shows the typical magnetic properties of a macroscopic ferrimagnet which are a magnetic compensation point and negative giant magnetoresistance (GMR). The Co-TbN mixture with 32 mole % TbN exhibits 0.72% GMR in fields up to 8 kOe at room temperature and 9% GMR at 250 K in 40 kOe. In the Co-TbN system, the dependence of GMR with temperature is quite different from that of previously studied GMR materials that have magnetoresistance decreases with increasing temperature. The GMR effect in the Co-TbN system increases with increasing temperature, because of the increase of ferromagnetic alignment of Co and TbN in a field at higher temperature. © 2001 American Institute of Physics.