Magnetic properties of partially devitrified Co-based metallic glass under high hydrostatic pressures

Abstract

Melt-spun Co₆₆Nb₉Cu₁Si₁₂B₁₂ metallic glass ribbon (T_C , ≈ 150 K) was used to produce nanocrystalline samples by annealing at 590 and 610°C for 1 h. Their magnetic characteristics were measured in a superconducting quantum interference device magnetometer as a function of temperature (10-250 K) in fields up to 3kOe under zero and approximately 7kbar hydrostatic pressure. The pressure shifts the Curie point of the amorphous matrix to lower temperature by −0.55 K kbar⁻¹. The difference between the zero-field-cooled and field-cooled dependences of the magnetization indicates mictomagnetic behaviour at low temperatures (T < T_Cc); for higher temperatures, the samples essentially act like an assembly of superparamagnetic particles. The analysis of the magnetization and demagnetization remanent states for both samples points to the presence of interactions, whose sensitivity to pressure strongly depends on the volume fraction of Co-rich crystallites.