MAGNETIC AND MAGNETOTRANSPORT PROPERTIES OF INTERMETALLIC SMMN2SI2

The magnetic properties of naturally layered intermetallic compound Sm Mn2Si2 with textured structure have been studied. There exist a ferrom agnetic transition at 35 K and two antiferromagnetic transitions at 12 0 and 230 K. The antiferromagnetic state below 230 K exhibits differen t magnetoresistance, with a negative magnetoresistance of 3%-4% for cu rrent I applied perpendicular to the c axis and with a positive magnet oresistance effect of about 4%-6% for current I parallel to the c axis . The observed magnetoresistance is likely to be related to magnetovol ume effects. In the ferromagnetic state, a positive magnetoresistance with a maximum increase of 22% under an applied field of 5 T is observ ed at 4 K, and both H perpendicular to I and H parallel to I configura tions show positive magnetoresistance. (C) 1997 American Institute of Physics.