Magnetic transitions and scaling behavior in Gd-rich glasses

The magnetic properties of amorphous alloys with composition Gdₓ{La}_{72{{-}}x}Ga₁₈{B}₁₀$ have been investigated using ac-susceptibilty and dc-magnetization techniques in the temperature range 4.2--300 K. This system shows double-transition behavior for x{}67 and paramagnetic--spin-glass transition behavior for x67. Time-dependent magnetization effects are present in the spin-glass phase and these effects vanish in finite fields, in qualitative agreement with mean-field theory. The magnetic isotherms around both the paramagnetic-ferromagnetic and ferromagnetic--spin-glass transitions scale according to the scaling hypothesis, and these results are discussed in some detail. A magnetic phase diagram for this system is obtained from the transition temperatures determined from scaling.