Giant magnetoresistance effect of Co-TbN macroscopic ferrimagnets

A new macroscopic ferrimagnet Co-TbN has TbN precipitates in a Co matrix. T he Co-TbN system shows the typical magnetic properties of a macroscopic fer rimagnet which are a magnetic compensation point and negative giant magneto resistance (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 differe nt from that of previously studied GMR materials that have magnetoresistanc e decreases with increasing temperature. The GMR effect in the Co-TbN syste m increases with increasing temperature, because of the increase of ferroma gnetic alignment of Co and TbN in a field at higher temperature. (C) 2001 A merican Institute of Physics.