Unusual magnetic and transport properties of layered compound ErMn6Sn6

The magnetic and magnetotransport properties of the polycrystalline ErMn6Sn6 compound have been investigated in the temperature interval of 5-380 K. The compound shows paramagetism, antiferromagnetism, and ferrimagnetism with decreasing temperature. In the antiferromagnetic state (67-362 K), the transition from antiferromagnetism to ferrimagnetism can be induced by an applied field, and the metamagnetic transition field increases from 0.2 kOe at 80 K to 15 kOe around 200 K and then decreases monotonously to 5 kOe at 330 K. The large magnetoresistance {MR=[R(H)-R(0)]x100%/R(0)} effect is observed with the metamagnetic behavior, such as -9.8% at 135 K under a field of 50 kOe. It is worth noting that ErMn6Sn6 displays the positive MR in the ferrimagnetic state and the negative one in the antiferromagnetic state, respectively, and the origin of the MR anomalies has been discussed. (C) 2004 American Institute of Physics.