Magnetic and magnetotransport properties of intermetallic SmMn2Si2

The magnetic properties of naturally layered intermetallic compound SmMn2Si2 with textured structure have been studied. There exist a ferromagnetic transition at 35 K and two antiferromagnetic transitions at 120 and 230 K. The antiferromagnetic state below 230 K exhibits different magnetoresistance, with a negative magnetoresistance of 3%-4% for current I applied perpendicular to the c axis and with a positive magnetoresistance effect of about 4%-6% for current I parallel to the c axis. The observed magnetoresistance is likely to be related to magnetovolume effects. In the ferromagnetic state, a positive magnetoresistance with a maximum increase of 22% under an applied field of 5 T is observed at 4 K, and both H perpendicular to I and H parallel to I configurations show positive magnetoresistance. (C) 1997 American Institute of Physics.