A study of magnetic interactions in M2EuRuO6 (M = Ca,Sr, Ba) by 151Eu Mössbauer spectroscopy |
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Authors: | TC Gibb R Greatrex |
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Institution: | Department of Inorganic and Structural Chemistry, The University, Leeds LS2 9JT, England |
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Abstract: | The series of compounds M2EuRuO6 (M = Ca, Sr, Ba) has been studied by 151Eu Mössbauer spectroscopy. X-Ray data show them to be structurally derived from the ABO3 perovskite lattice, but only the Ba compound gives positive evidence to suggest ordering of the cations. The 151Eu resonance shows magnetic hyperfine splitting at 4.2 K. The Ru5+OEu3+ORu5+ exchange takes place by admixture of low-lying excited states into the diamagnetic J = 0 ground-state of the Eu3+. The Curie temperatures are approximately 18, 31, and 42 K for the Ca, Sr, and Ba compounds. Detailed analysis shows that substantial disorder of cations occurs, being quite large for Ca, <8% for Sr, and <5% for Ba. However, it appears that considerable canting of the Ru5+ spins takes place in the Ba compound immediately below the Curie temperature as a result of the disorder and low anisotropy at the Ru sites. This effect is much reduced in the more distorted Sr compound. |
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