Study of spin-phonon coupling in LiFe<inf>1-x</inf>Mn<inf>x</inf>PO<inf>4</inf>olivines
- 주제(키워드) Electrochemical activity , Internal/external mode , LiFe<inf>1-x</inf>Mn<inf>x</inf>PO<inf>4</inf> olivine , Raman spectroscopy , Spin-phonon coupling
- 등재 SCIE, SCOPUS
- 발행기관 John Wiley and Sons Ltd
- 발행년도 2015
- 총서유형 Journal
- URI http://www.dcollection.net/handler/ewha/000000118049
- 본문언어 영어
- Published As http://dx.doi.org/10.1002/jrs.4736
- 저작권 이화여자대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
LiFe<inf>1-x</inf>Mn<inf>x</inf>PO<inf>4</inf> olivines are promising material for improved performance of Li-ion batteries. Spin-phonon coupling of LiFe<inf>1-x</inf>Mn<inf>x</inf>PO<inf>4</inf> (x=0, 0.3, 0.5) olivines is studied through temperature-dependent Raman spectroscopy. Among the observed phonon modes, the external mode at ~263cm-1 is directly correlated with the motions of magnetic Fe2+/Mn2+ ions. This mode displays anomalous temperature-dependent behavior near the Néel temperature, indicating a coupling of this mode with spin ordering. As Mn doping increases, the anomalous behavior becomes clearly weaker, indicating the spin-phonon coupling quickly decreases. Our analyses show that the quick decrease of spin-phonon coupling is due to decrease of the strength of spin-phonon coupling, but not change of spin-ordering feature with Mn doping. Importantly, we suggest that the low electrochemical activity of LiMnPO<inf>4</inf> is correlated with the weak spin-phonon coupling strength, but not with the weak ferromagnetic ground state. Our work would play an important role as a guide in improving the performances of future Li-ion batteries. © 2015 John Wiley & Sons, Ltd.
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