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

Journal Article · Wed May 07 04:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4870582· OSTI ID:22273591

Kennedy, Shane ^[1]; Wang, Jianli ^[1]; Campbell, Stewart ^[2]; Hofmann, Michael ^[3]; Dou, Shixue ^[4]

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1. The Bragg Institute, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)
2. School of Physical, Environmental and Mathematical Sciences, University of New South Wales, Canberra, ACT (Australia)
3. Forschungs-Neutronenquelle Heinz Maier-Leibnitz, Technische Universität München, Garching (Germany)
4. Institute for Superconductivity and Electronic Materials, University of Wollongong, Wollongong, NSW (Australia)

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 metalloid 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.

• OSTI ID: 22273591
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 17 Vol. 115; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

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