Magnetic and Electronic Properties of Eu₄Sr₄Ga₁₆Ge₃₀
Magnetization, static and ac magnetic susceptibility, nuclear forward scattering, and electrical resistivity measurements have been performed on polycrystalline Eu4 Sr4 Ga16 Ge30, a type I clathrate that has divalent strontium and europium ions encapsulated within a Ga-Ge framework. These data are compared with those of type I clathrates Eu8 Ga16 Ge30 and Eu6 Sr2 Ga16 Ge30. The ferromagnetic ordering of these Eu-containing clathrates is substantially altered by the incorporation of strontium, as compared to Eu8 Ga16 Ge30. Ferromagnetism, accompanied by a relatively large negative magnetoresistance, is observed below 15 and 20 K in Eu4 Sr4 Ga16 Ge30 and Eu6 Sr2 Ga16 Ge30, respectively. An effective magnetic moment of 7.83 μB per Eu ion is observed above 30 K for Eu4 Sr4 Ga16 Ge30, a moment which is close to the free-ion moment of 7.94 μB per europium(II) ion. © 2006 The American Physical Society.
G. T. Woods et al., "Magnetic and Electronic Properties of Eu₄Sr₄Ga₁₆Ge₃₀," Physical Review B - Condensed Matter and Materials Physics, American Physical Society (APS), Jan 2006.
The definitive version is available at http://dx.doi.org/10.1103/PhysRevB.73.174403
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