First-order phase transition at the curie temperature in MnAs and MnAs 0.9Sb0.1

Fumihiro Ishikawa, Keiichi Koyama, Kazuo Watanabe, Tetsuya Asano, Hirofumi Wada

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

Structural transformations of MnAs and MnAs0.9Sb0.1 were investigated by X-ray diffraction in high magnetic fields up to 5 T. The temperature dependence of the magnetization was measured in a magnetic field of 0.01 T and the Curie temperature TC was determined to be 315 K for MnAs and 290 K for MnAs0.9Sb0.1 during heating process. For both compounds, a metamagnetic transition from a paramagnetic to a ferromagnetic state was observed above TC. The X-ray diffraction profile at 319 K for MnAs showed a single phase of an orthorhombic MnP-type structure in zero field. An applied magnetic field of 3 T induced the appearance of a hexagonal NiAs-type structure. On further increase of the magnetic field, a single phase with a hexagonal structure was realized above 3.5 T in a forced-ferromagnetic state. The X-ray diffraction profile at 295 K for MnAs 0.9Sb0.1 showed a hexagonal NiAs-type structure. The coexistence of ferromagnetic and paramagnetic states with different lattice parameters was confirmed in a magnetic field of 2.5 T. The volume expansion induced by a magnetic field was found to be 2.1% for MnAs and 1.1% for MnAs 0.9Sb0.1.

Original languageEnglish
Article number084604
Journaljournal of the physical society of japan
Volume75
Issue number8
DOIs
Publication statusPublished - 2006 Aug

Keywords

  • Metamagnetic transition
  • MnAs
  • Structural transformation
  • X-ray diffraction

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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