Neutron Scattering Study on Commensurate and Incommensurate Antiferromagnetic Phases in UPd₂Si₂under Uniaxial Stress

Abstract

The nature of competition between incommensurate (IC) and commensurate (C) antiferromagnetic (AF) orders in UPd 2 Si 2 was investigated by performing elastic neutron scattering experiments under uniaxial stress σ. It is found that applying σ along tetragonal [010] direction reduces the IC-AF order, and then stabilizes the C-AF order. The transition temperature from IC-to C-AF phases T Nl is enhanced from 109 K (σ = 0) to 112.5 K at (0.8 GPa), while the onset of IC-AF transition T Nh is unchanged from 132 K under σ. In addition, c-axis component q z of the IC-AF modulation at 115 K also increases from 0.736 (σ = 0) to 0.747 (0.8 GPa). The magnitude of C-AF moment at 5 K is estimated to be 2.2 µ B /U in the entire σ range presently investigated (σ ≤ 0.8 GPa). These features are similar to those obtained from the investigations using hydrostatic pressure p, indicating that applications of p and σ || [010] commonly induce the crystal strains which inherently affect a delicate balance of frustrated magnetic interactions between uranium 5f moments.

Uniaxial-Pressure Effects on Spin-Driven Lattice Distortions in Geometrically Frustrated Magnets CuFe1-xGaxO2 (x=0, 0.035)

“…There have also been several other neutron diffraction and magnetization measurements on frustrated magnets under uniaxial pressure. 7,8) Although these previous works have suggested that the applied uniaxial pressure changes the degree of magnetic frustration via the lattice degree of freedom, the uniaxial-pressure-induced changes in the crystal structures were not investigated in detail. In this paper, we present a synchrotron radiation x-ray diffraction study on the frustrated magnets CuFeO 2 (CFO) and CuFe 1Àx Ga x O 2 (CFGO) under applied uniaxial pressure, revealing how the uniaxial pressure changes the crystal structure and relieves the magnetic frustration.…”