Magnetic properties of B2-structure CoZr upon ball milling

Magnetization measurements of B2-structure CoZr after high-energy ball milling have been performed at 4.2 K in the Amsterdam High Field Installation in fields up to 35 T. It turns out that the magnetic behavior of the ball-milled CoZr is drastically different from the unmilled sample. The magnetization at 21 T increases abruptly in the early state of milling due to the introduction of anti-site disorder in the B2-1attice. Upon amorphization the magnetization decreases. The magnetization of both the disordered crystalline compound and the amorphous material is not saturated up to 35 T. AC magnetic susceptibility and DC low-field magnetization measurements show that both disordered crystalline and amorphous CoZr exhibit a magnetic transition from the paramagnetic to the spin-glass-like state upon cooling with ordering temperatures of about 35 and 11 K, respectively, whereas the perfectly ordered (unmilled) compound is a paramagnet down to 4.2 K.