SCALING BEHAVIOR OF MAGNETIZATION FOR TEMPERATURES IN THE VICINITY OF, AND FAR FROM, THE FERROMAGNETIC-PARAMAGNETIC PHASE-TRANSITION IN AMORPHOUS FE-90-XCOXZR10 AND FE90-Y ALLOYS(YZR10)

Asymptotic critical exponents and amplitudes as well as the leading 'c orrection-to-scaling' (CTS) amplitudes have been accurately determined through an elaborate analysis of magnetization data taken on amorphou s Fe90-xCoxZr10(0 less than or equal to x less than or equal to 6) and Fe90+yZr10-y(y = 0, 1) alloys in the critical region. Consistent with the Harris criterion, asymptotic critical exponents and the universal amplitude ratio Dm(0)(delta)/h(0) do not depend on composition and po ssess values the same as those predicted by theory for an ordered spin system with n = d = 3. The leading amplitude ratio a(M1)(-)/a(chi 1)( +), which is characteristic of ferromagnets with quenched random disor der and for which no theoretical estimate is presently available, is c omposition independent and probably universal. The fraction of spins a ctually participating in the ferromagnetic (FM)-paramagnetic (PM) tran sition occurring at T = T-C is small and increases with Co substitutio n. While the magnetic equation of state (MES) in linear scaling variab les and its counterpart in nonlinear scaling variables, valid for a se cond-order phase transition, form equivalent descriptions of magnetiza tion, M(T, H), data in the asymptotic critical region (ACR), the latte r version of MES alone reproduces closely the observed M(T, H) behavio ur in a temperature range as wide as 0.45T(C) less than or similar to T less than or similar to 1.5T(C). Nonanalytic CTS terms dominate over analytic ones in the ACR but the reverse is true for temperatures out side the ACR. Initial susceptibility follows the generalized Curie-Wei ss law from T-C to similar or equal to 1.5T(C) and thereby permits an accurate determination of atomic moment in the PM state. The results o f the present investigation provide strong experimental evidence for w eak itinerant ferromagnetism in the glassy alloys in question.