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ErFe 6 Sn 6

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ErFe 6 Sn 6

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  1. Independent magnetic ordering of the Er and Fe sublattices in ErFe6Sn6J.M. Cadogan and D.H. RyanDepartment of Physics and Astronomy, University of ManitobaWinnipeg, MB, R3T 2N2, Canada E-mail: cadogan@physics.umanitoba.caDepartment of Physics, McGill UniversityMontreal, QC, H3A 2T8, Canada E-mail: dhryan@physics.mcgill.ca

  2. ErFe6Sn6 is orthorhombic (Cmcm) There are two Er sites, five Fe sites and ten Sn sites RFe6Ge6 and RFe6Sn6 intermetallics show the somewhat unusual phenomenon of independent magnetic ordering of the R and Fe sublattices [1]. Fe orders antiferromagnetically at 555 K. The Er ordering takes place at 5 K, without affecting the Fe order [2]. The Er is located between ferromagnetic planes of Fe, whose antiferromagnetic interplanar coupling leads to a zero net exchange field at the Er site. ErFe6Sn6

  3. Mössbauer spectroscopyof 166Er The 80.6 keV Mössbauer gamma-ray arises from the transition between the I=2 excited nuclear state and the I =0 ground state of the 166Er nucleus. 166Ho 27 hr b− I=2 80.6 keV, 1.9 ns 0 keV I=0 166Er A more detailed description of the 166Er experiment can be found in our article on Er3Ge4

  4. Fe magnetic ordering at 555 K detected by Differential Scanning Calorimetry Magnetic ordering in ErFe6Sn6 Er magnetic ordering at 5 K detected by ac-susceptibility

  5. Magnetization of the Er sublattice • Magnetometry at 2 K shows that the Er sublattice magnetic order comprises both FM and AF components • M remains unsaturated up to 9 T.

  6. Neutron powder diffraction Hahn-Meitner Institute, Berlin The magnetic scattering from the Er sublattice is quite weak.

  7. A Mössbauer triptych 57Fe 119Sn 166Er Note the different velocity scales!

  8. The 57Fe Mössbauer spectrum shows the (AF) order of the Fe sublattice, with an Fe moment of 1.7 mB at RT. • The 119Sn Mössbauer spectrum shows two components, one of which is magnetically split. Sn is non-magnetic so the Sn nuclei only see transferred hyperfine fields from their (magnetic) surroundings. The relative areas of the two components in the 119Sn Mössbauer spectrum are fully consistent with the magnetic structures of the Er sublattices (sites) determined by neutron diffraction. As such, the 119Sn Mössbauer work provides an excellent verification of the neutron diffraction results. • The 166Er Mössbauer spectrum obtained at 2 K shows that the Er3+ magnetic moment in ErFe6Sn6 is 8.5(1) mB, close to its free-ion value (9 mB)

  9. Er sublattice magnetic order in ErFe6Sn6 Er 4c1 site. Er 4c2 site. Open circles represent the z =1/4 plane, Hatched circles represent the z =3/4 plane.

  10. References • This study demonstrates the powerful complementarity of Mössbauer Spectroscopy (a local magnetic probe) and Neutron Diffraction (an extended-scale measurement) • Neutron diffraction gives the FM and AF components of the magnetic order • 166Er Mössbauer Spectroscopy gives the total local Er3+ moment. • 57Fe Mössbauer Spectroscopy gives the total local Fe moment. • 119Sn Mössbauer Spectroscopy provides verification of the magnetic structure. [1] J.M. Cadogan and D.H. Ryan, J. Alloys. Comp. 326, 166-73 (2001) [2] J.M. Cadogan et al. J. Phys.: Condensed Matter 15, 1757-71 (2003)

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