کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1517083 | 1511602 | 2008 | 6 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Mössbauer spectroscopic study of the thermal spin crossover in [Fe(II)(isoxazole)6](ClO4)2 Mössbauer spectroscopic study of the thermal spin crossover in [Fe(II)(isoxazole)6](ClO4)2](/preview/png/1517083.png)
The 57Fe Mössbauer spectroscopy of mononuclear [Fe(II)(isoxazole)6](ClO4)2 has been studied to reveal the thermal spin crossover of Fe(II) between low-spin (S=0) and high-spin (S=2) states. Temperature-dependent spin transition curves have been constructed with the least-square fitted data obtained from the Mössbauer spectra measured at various temperatures between 84 and 270 K during a cooling and heating cycle. This compound exhibits an unusual temperature-dependent spin transition behaviour with TC(↓)=223 and TC(↑)=213 K occurring in the reverse order in comparison to those observed in SQUID observation and many other spin transition compounds. The compound has three high-spin Fe(II) sites at the highest temperature of study of which two undergo spin transitions. The compound seems to undergo a structural phase transition around the spin transition temperature, which plays a significant role in the spin crossover behaviour as well as the magnetic properties of the compound at temperatures below TC. The present study reveals an increase in high-spin fraction upon heating in the temperature range below TC, and an explanation is provided.
Journal: Journal of Physics and Chemistry of Solids - Volume 69, Issue 11, November 2008, Pages 2713–2718