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Title: Magnetization-steps in Y₂CoMnO₆ double perovskite: The role of antisite disorder

Antisite disorder is observed to have significant impact on the magnetic properties of the double perovskite Y²CoMnO₆ which has been recently identified as a multiferroic. A paramagnetic-ferromagnetic phase transition occurs in this material at Tc ≈ 75 K. At 2 K, it displays a strong ferromagnetic hysteresis with a significant coercive field of Hc ≈ 15 kOe. Sharp steps are observed in the hysteresis curves recorded below 8 K. In the temperature range 2 K ≤ T ≤ 5 K, the hysteresis loops are anomalous as the virgin curve lies outside the main loop. The field-cooling conditions as well as the rate of field-sweep are found to influence the steps. Quantitative analysis of the neutron diffraction data shows that at room temperature, Y₂CoMnO₆ consists of 62% of monoclinic P2₁/n with nearly 70% antisite disorder and 38% Pnma. The bond valence sums indicate the presence of other valence states for Co and Mn which arise from disorder. We explain the origin of steps by using a model for pinning of magnetization at the antiphase boundaries created by antisite disorder. The steps in magnetization closely resemble the martensitic transformations found in intermetallics and display first-order characteristics as revealed in the Arrott's plots.
Authors:
; ;  [1] ;  [2] ; ;  [3] ; ;  [4]
  1. Jülich Center for Neutron Sciences-2/Peter Grünberg Institute-4, Forschungszentrum Jülich GmbH, 52425 Jülich (Germany)
  2. Low Temperature Physics Laboratory, Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India)
  3. Department of Physics, Indian Institute of Science, C. V. Raman Avenue, Bangalore 560012 (India)
  4. Institut Laue-Langevin, BP 156, 38042 Grenoble Cedex 9 (France)
Publication Date:
OSTI Identifier:
22305710
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 12; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COBALT COMPOUNDS; FERROMAGNETISM; INTERMETALLIC COMPOUNDS; MAGNETIC PROPERTIES; MAGNETIZATION; MANGANATES; MONOCLINIC LATTICES; NEUTRON DIFFRACTION; PARAMAGNETISM; PEROVSKITE; PHASE TRANSFORMATIONS; TEMPERATURE RANGE 0065-0273 K; TEMPERATURE RANGE 0273-0400 K; YTTRIUM COMPOUNDS