Details

Autor(en) / Beteiligte

• Biswas, Sumita
• Sabyasachi, Sk
• Bhaumik, Asim
• Ray, Ruma

Titel

Magnetic Memory Effects in /\gamma\hbox}} Nanostructures

Ist Teil von

• IEEE transactions on magnetics, 2014-03, Vol.50 (3), p.11-17

Ort / Verlag

IEEE

Erscheinungsjahr

2014

Link zum Volltext

• IEEE_Xplore

Quelle

IEEE Xplore (IEEE/IET Electronic Library - IEL)

Beschreibungen/Notizen

• We report an unusual consequence of magnetic memory effect in Fe/γ-Fe 2 O 3 nanostructures, which is prepared using an electrochemical route. Chemical phases of Fe/γ-Fe 2 O 3 nanostructures are characterized by X-ray diffraction, optical, and Mössbauer spectroscopic studies. The static and dynamic aspects of dc magnetization studies are carried out. Thermal variation of zero-field-cooled (ZFC) magnetization displays a signature of blocking temperature (T B ) at 215 K. Another broadened peak is also evident in the field-cooled (FC) magnetization at 40 K (T G ). Signature of memory effect is observed below TG after cooling the sample both in ZFC and FC protocols. Appearance of memory effect in the ZFC protocol confirms spin-glass-like state below T G . Interestingly, memory effect is absent below T B even in FC protocol, although a large particle size distribution is noticed in the Fe/γ-Fe 2 O 3 nanostructures. The results address the fundamental question whether substantial particle size distribution is sufficient enough for the memory effect in the FC protocol as found in the literatures.