Stabilization of an ambient pressure, collapsed tetragonal phase in CaFe2As2 and tuning of the orthorhombic / antiferromagnetic transition temperature by over 70 K by control of nano-precipitates

Abstract

We have found a remarkably large response of the transition temperature of CaFe2As2 single crystals grown out of excess FeAs to annealing / quenching temperature. Whereas crystals that are annealed at 400 C exhibit a first order phase transition from a high temperature tetragonal to a low temperature orthorhombic and antiferromagnetic state near 170 K, crystals that have been quenched from 960 C exhibit a transition from a high temperature tetragonal phase to a low temperature, non-magnetic, collapsed tetragonal phase below 100 K. By use of temperature dependent electrical resistivity, magnetic susceptibility, X-ray diffraction, Mossbauer spectroscopy and nuclear magnetic resonance measurements we have been able to demonstrate that the transition temperature can be reduced in a monotonic fashion by varying the annealing / quenching temperature from 400 to 850 C with the low temperature state remaining antiferromagnetic for transition temperatures larger than 100 K and becoming collapsed tetragonal / non-magnetic for transition temperatures below 90 K. This suppression of the orthorhombic / antiferromagnetic phase transition and its ultimate replacement with the collapsed tetragonal / non-magnetic phase is similar to what has been observed for CaFe2As2 under hydrostatic pressure. Transmission electron microscopy studies indicate that there is a temperature dependent, width of formation of CaFe2As2 with a decreasing amount of excess Fe and As being soluble in the single crystal at lower annealing temperatures. For samples quenched from 960 C there is a fine (of order 10 nm), semi-uniform distribution of precipitate that can be associated with an average strain field whereas for samples annealed at 400 C the excess Fe and As form mesoscopic grains that induce little strain throughout the CaFe2As2 lattice.

References in corpus (15)

• Pressure induced superconductivity in CaFe${}_2$As${}_2$
• Effects of Co substitution on thermodynamic and transport properties and anisotropic $H_{c2}$ in Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$ single crystals
• Pressure-induced volume-collapsed tetragonal phase of CaFe2As2 as seen via neutron scattering
• Lattice and magnetic instabilities in CaFe2As2: A single crystal neutron diffraction study
• First order structural phase transition in CaFe${}_2$As${}_2$
• Different resistivity response to spin density wave and superconductivity at 20 K in $C{a}_{1-x}N{a}_{x}F{e}_{2}A{s}_2$
• The Absence of Superconductivity in Single Phase CaFe2As2 under Hydrostatic Pressure
• Lattice collapse and quenching of magnetism in CaFe2As2 under pressure: A single crystal neutron and x-ray diffraction investigation
• Synthesis and Properties of CaFe${}_2$As${}_2$ Single Crystals
• Pressure-induced superconductivity in single crystal CaFe2As2
• Presure-Induced Superconducting State of Antiferromagnetic CaFe${}_2$As${}_2$
• Heat capacity study of BaFe${}_2$As${}_2$: effects of annealing
• Suppression of antiferromagnetic spin fluctuations in the collapsed tetragonal phase of CaFe2As2
• First order magnetic transition in single crystal CaFe${}_2$As${}_2$ detected by ${}^{75}$As NMR
• A crystallographic phase transition within the magnetically ordered state of Ce_2Fe_17

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