Superparamagnetic spin dynamics studied using selective excitation double Mössbauer spectroscopy.
نویسندگان
چکیده
A detailed study of spin dynamics in a 6 nm Fe3O4 ferrofluid using a substantially improved selective excitation double Mossbauer (SEDM) experimental technique has led to the unambiguous separation of static disorder, collective excitations, and moment reversals. Superparamagnetic spin flips have been observed through the appearance of an additional line in the SEDM spectrum, defining the energy transitions during relaxation, with frequencies of 2.5+/-0.3 MHz at 70 K to 9.7+/-1.0 MHz at 110 K. SEDM offers a precise window into the dynamics and blocking behavior of fine particle systems.
منابع مشابه
Dynamics in fine particle magnets
Several magnetic fine particle systems have been studied with selective excitation double Mössbauer ~SEDM! spectroscopy. Static disorder, collective excitations, and superparamagnetic spin flips are all detected and their contributions quantified. Zero-field muon spin relaxation spectroscopy has been used to confirm these observations in one sample. A theoretical description of SEDM spectra in ...
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ورودعنوان ژورنال:
- Physical review letters
دوره 85 14 شماره
صفحات -
تاریخ انتشار 2000