Ageing effects in nanocrystalline Co50Ni50 and Fe50Ni50 alloy: Role of magnetic anisotropy

作者：De D; Dey K; Majumdar S; Giri S^*

来源：Solid State Communications, 2012, 152(19): 1857-1861.

DOI：10.1016/j.ssc.2012.07.012

• Nanocrystalline alloy
• Ageing effect

Nanocrystalline Co50Ni50 (CN8.6) and Fe50Ni50 (FN9.5) alloys embedded in an amorphous silica host are considered for the study with same volume fraction, phi = 10% and nearly close average particle sizes 8.6 and 9.5 nm, respectively. The contrast magnetic properties together with anomalous ageing or memory effect are noticed for these nanocrystalline alloys. Dc magnetization results indicate superparamagnetic-like behaviour for CN8.6 and superspin glass-like behaviour for FN9.5. The ageing effect in field-cooled protocol is apparent below blocking temperature for CN8.6 which is unexpectedly absent for FN9.5. Rather, ageing effect is evident at low temperature below superspin-glass transition temperature for FN9.5. The ageing effect recorded in zero-field cooled protocol for FN9.5 suggests cooperative spin correlation as evident in atomic spin-glass system, which is absent for CN8.6. The contrast magnetic properties are correlated with the magnetic anisotropies of these nanocrystalline alloys.

• 出版日期2012-10