Long-range magnetic phase transitions and negative magnetoresistance of divalent Eu in Eu2Cu5Ni5 phase

Michael O. Ogunbunmi, André M. Strydom

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

We report the synthesis and physical properties of a new ternary Eu2Cu5Ni5 phase which crystallizes in the orthorhombic space group Pmmm, No. 47, Z = 1, with lattice parameters; a = 4.015(4), b = 4.921(2) and c = 8.621(3) Å. Analysis from magnetic susceptibility χdc(T) results reveal an effective magnetic moment μeff = 7.8 μB/Eu that is comparable to the theoretical value of 7.93 μB for a divalent Eu2+ ion. The Eu2+ electronic state of 4f7 is well localized in this phase and the results preclude both the Cu and Ni sub-lattices from bearing a magnetic moment. Two long-range phase transitions pertaining to the Eu2+ moments are observed at TC1 = 72 K and TC2 = 47.2 K, followed by another anomaly at TSR = 22 K, attributed to a spin re-orientation of Eu moments. The Seebeck coefficient S(T) attains a value of − 16.7 μV/K at room temperature (RT) and indicates that the electrons are the dominant charge carriers. Evidence from the electrical transport reveals a metallic behavior with the magnetotransport showing a negative magnetoresistance below RT.

Original languageEnglish
Article number161454
JournalJournal of Alloys and Compounds
Volume887
DOIs
Publication statusPublished - 20 Dec 2021

Keywords

  • Divalent Eu electronic state
  • EuCuNi
  • Long-range magnetic ordering
  • Negative magnetoresistance
  • Spin re-orientation

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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