Magnetic properties and electronic structures of RCo2-xSix (R=Gd, Y) compounds

Magnetic measurements and band structure calculations were performed on YCo 2-xSix and GdCo2-xSix systems. For the YCo2-xSix exchange enhanced paramagn ets the magnetic susceptibilities have maxima and at temperatures T >T* a C urie-Weiss type behavior is evidenced. The effective cobalt moments decreas e when silicon content increases. This fact was attributed to p-d hybridiza tion effects as evidenced from band structure calculations. The magnetic be havior of cobalt was analyzed in spin fluctuations model. The saturation mo ments at 4.2 K in GdCo2-xSix system are in agreement with those obtained fr om band structure calculations. The effective cobalt moments in GdCo2-xSix compounds are smaller than those determined in YCo2-xSix system. This fact was attributed to partial quenching of spin fluctuations by internal field. (C) 2001 Elsevier Science B.V. All rights reserved.