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arXiv · 1103.2446

Varying Eu$^{2+}$ magnetic order in EuFe$_2$As$_2$ by chemical pressure

Sina Zapf·Dan Wu·Lapo Bogani·Hirale S. Jeevan·Philipp Gegenwart·Martin Dressel
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Abstract

Among iron 122 pnictide superconductors, the EuFe$_2$As$_2$ series draws particular interest because, in addition to superconductivity or the long-range spin-density-wave order in the Fe subsystem, the localized Eu$^{2+}$ magnetic moments order at low temperatures. Here we present a novel scheme of how the spins align in the Eu compounds when pressure varies the coupling; we explain magnetization measurements on EuFe$_2$(As$_{1-x}$P$_x$)$_2$ single crystals as well as other observations of the Eu$^{2+}$ ordering previously reported in literature. The magnetic moments of the Eu$^{2+}$ ions are slightly canted even in the parent compound EuFe$_2$As$_2$, yielding a ferromagnetic contribution along the $c$-direction that becomes stronger with pressure. Reducing the interlayer distance even further, the antiferromagnetic coupling of the $ab$ planes finally turns ferromagnetic.

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Sina Zapf, Dan Wu, Lapo Bogani, Hirale S. Jeevan, Philipp Gegenwart, Martin Dressel. 2011-03-12. Varying Eu$^{2+}$ magnetic order in EuFe$_2$As$_2$ by chemical pressure. https://arxiv.org/abs/1103.2446

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