Magnetic and Thermal Properties of $\lambda$-(BETS)2FeCl4 System ---Fe 3d Spin in Antiferromagnetic Insulating Phase

A quasi-two-dimensional organic conductor $\lambda$-(BETS) 2 FeCl 4 [BETS = bis(ethylenedithio)tetraselenafulvalene] exhibits a new type of phase transition from a paramagnetic metal (PM) to an antiferromagnetic insulator (AFI) at a transition temperature ($T_{\text{MI}}$) of 8.3 K under zero magnet...

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Bibliographic Details
Published in:Journal of the Physical Society of Japan 2011-06, Vol.80 (6), p.063601-063601-3
Main Authors: Akiba, Hiroshi, Nobori, Kento, Shimada, Kazuo, Nishio, Yutaka, Kajita, Koji, Zhou, Biao, Kobayashi, Akiko, Kobayashi, Hayao
Format: Article
Language:English
Online Access:Get full text
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Summary:A quasi-two-dimensional organic conductor $\lambda$-(BETS) 2 FeCl 4 [BETS = bis(ethylenedithio)tetraselenafulvalene] exhibits a new type of phase transition from a paramagnetic metal (PM) to an antiferromagnetic insulator (AFI) at a transition temperature ($T_{\text{MI}}$) of 8.3 K under zero magnetic field. We studied its thermodynamic properties and found a six-level Schottky hump in its specific heat and a broad shoulder in its magnetic susceptibility below $T_{\text{MI}}$. These anomalies are explained by a new model in which the 3 d spin maintains the paramagnetic states against the antiferromagnetic ordering of the $\pi$ spin.
ISSN:0031-9015
1347-4073
DOI:10.1143/JPSJ.80.063601