Magnetic phase diagram of Eu1-xLaxFe2As2 single crystals

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:321

Article

Wu, T.¹  Wu, G.¹  Chen, H.¹  Xie, Y. L.¹  Liu, R. H.¹  Wang, X. F.¹  Chen, X. H.¹ 

[1] Univ Sci & Technol China, Dept Phys, Hefei Natl Lab Phys Sci Microscale, Hefei 230026, Anhui, Peoples R China

关键词: Metamagnetism;    Magnetic property;    Magnetic phase diagram;   

DOI  :  10.1016/j.jmmm.2009.07.043

来源: Elsevier

【 摘 要 】

We have systematically measured resistivity, susceptibility and specific heat under different magnetic fields (H) in Eu1-xLaxFe2As2 single crystals. It is found that a metamagnetic transition from A-type antiferromagnetism to ferromagnetism occurs at a critical field for magnetic sublattice of Eu2+ ions. The jump of specific heat is suppressed and shifts to low temperature with increasing H up to the critical value, then shifts to high temperature with further increasing H. Such behavior supports the metamagnetic transition. Further, a two fold in-plane magnetization is found in antiferromagnetic state which is similar to spin density wave (SDW) order. In contrast, isotropicin-plane magnetization is presented in both ferromagnetic and paramagnetic states. Moreover, ferromagnetic state becomes more easily established under external field with suppressing SDW order. An anisotropic exchange model is proposed to understand our findings. Our results suggest that metamagnetism of Eu2+ ions is somewhat related to SDW order. Finally, detailed H-T phase diagrams for x=0 and 0.15 crystals are given, and possible magnetic structure is proposed. (C) 2009 Published by Elsevier B.V.

【 授权许可】

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