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Title: Pressure induced magneto-structural phase transitions in layered RMn{sub 2}X{sub 2} compounds (invited)

We have studied a range of pseudo-ternaries derived from the parent compound PrMn{sub 2}Ge{sub 2}, substituting for each constituent element with a smaller one to contract the lattice. This enables us to observe the magneto-elastic transitions that occur as the Mn-Mn nearest neighbour distance is reduced and to assess the role of Pr on the magnetism. Here, we report on the PrMn{sub 2}Ge{sub 2−x}Si{sub x}, Pr{sub 1−x}Y{sub x}Mn{sub 2}Ge{sub 2}, and PrMn{sub 2−x}Fe{sub x}Ge{sub 2} systems. The pressure produced by chemical substitution in these pseudo-ternaries is inherently non-uniform, with local pressure variations dependent on the local atomic distribution. We find that concentrated chemical substitution on the R or X site (e.g., in Pr{sub 0.5}Y{sub 0.5}Mn{sub 2}Ge{sub 2} and PrMn{sub 2}Ge{sub 0.8}Si{sub 1.2}) can produce a separation into two distinct magnetic phases, canted ferromagnetic and canted antiferromagnetic, with a commensurate phase gap in the crystalline lattice. This phase gap is a consequence of the combination of phase separation and spontaneous magnetostriction, which is positive on transition to the canted ferromagnetic phase and negative on transition to the canted antiferromagnetic phase. Our results show that co-existence of canted ferromagnetic and antiferromagnetic phases depends on chemical pressure from the rare earth and metalloidmore » sites, on local lattice strain distributions and on applied magnetic field. We demonstrate that the effects of chemical pressure bear close resemblance to those of mechanical pressure on the parent compound.« less
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [5]
  1. The Bragg Institute, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)
  2. (Australia)
  3. School of Physical, Environmental and Mathematical Sciences, University of New South Wales, Canberra, ACT (Australia)
  4. Forschungs-Neutronenquelle Heinz Maier-Leibnitz, Technische Universität München, Garching (Germany)
  5. Institute for Superconductivity and Electronic Materials, University of Wollongong, Wollongong, NSW (Australia)
Publication Date:
OSTI Identifier:
22273591
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 17; Conference: 55. annual conference on magnetism and magnetic materials, Atlanta, GA (United States), 14-18 Nov 2010; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANTIFERROMAGNETISM; CONCENTRATION RATIO; CRYSTAL LATTICES; GERMANIDES; IRON COMPOUNDS; MAGNETIC FIELDS; MAGNETOSTRICTION; MANGANESE COMPOUNDS; PHASE TRANSFORMATIONS; PRASEODYMIUM COMPOUNDS; PRESSURE DEPENDENCE; SILICIDES; STRAINS; VARIATIONS; YTTRIUM COMPOUNDS