Paramagnetic Metal–Antiferromagnetic Insulator Transition of λ-BETS2FexGa1-xCl4 System

Autor:	Tajima Naoya, Zhou Biao, Shimada Kazuo, Kajita Koji, Nishio Yutaka, Kobayashi Akiko, Kobayashi Hayao, Sugawara Hiroki, Akiba Hiroshi, Nobori Kento
Rok vydání:	2012
Předmět:	Phase transition Materials science Condensed matter physics Transition temperature General Physics and Astronomy Magnetic field Metal Magnetic anisotropy Paramagnetism visual_art visual_art.visual_art_medium Antiferromagnetism Condensed Matter::Strongly Correlated Electrons Ground state
Zdroj:	Journal of the Physical Society of Japan. 81:053601
ISSN:	1347-4073 0031-9015
DOI:	10.1143/jpsj.81.053601
Popis:	The quasi-two-dimensional organic conductor λ-BETS 2 FeCl 4 [BETS = bis(ethylenedithio) tetraselenafulvalene] transforms from a paramagnetic metal (PM) to an antiferromagnetic insulator (AFI) at a transition temperature T MI of 8.3 K under a zero magnetic field. To investigate the mechanism of this PM–AFI phase transition, we studied the Fe 3 d spin content dependence of the AFI ground state by measuring the specific heat of the mixed crystal λ-BETS 2 Fe x Ga 1- x Cl 4 at temperatures as low as 0.2 K. The increasing Fe 3 d spin density enhances the internal magnetic field caused by π spin antiferromagnetic (AF) ordering. It was confirmed that the Fe 3 d spin provides favorable conditions for this mysterious PM–AFI phase transition. We propose that this phase transition originates from the magnetic anisotropy introduced by the π– d interaction, which suppresses the low-dimensional fluctuation in the π spin system.
Databáze:	OpenAIRE
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