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In situ control of the helical and skyrmion phases in Cu2OSeO3 using high-pressure helium gas up to 5 kbar

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Author Crisanti M., Reynolds N., Živković I., Magrez A., Rønnow H. M., Cubitt R., White J. S.,
Project Exploration of emerging magnetoelectric coupling effects in new materials
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Original article (peer-reviewed)

Journal Physical Review B
Volume (Issue) 101(21)
Page(s) 214435 - 214435
Title of proceedings Physical Review B
DOI 10.1103/physrevb.101.214435

Open Access

Type of Open Access Publisher (Gold Open Access)


We report a small-angle neutron scattering study of the helical and skyrmion lattice order in singlecrystal Cu2OSeO3 under quasihydrostatic helium gas pressures up to 5 kbar. By using helium gas as the pressure-transmitting medium (PTM) we ensure pressure application with improved hydrostaticity at cryogenic temperatures compared with previous reports where liquid PTMs were used. For 5-kbar He gas pressure we observe modest changes of the ambient pressure phase diagram; the critical temperature Tc changes by +2.8(2)%, while in the low-T limit the helical propagation vector |q| changes by −0.5(2)%, the lower critical field Hc1 changes by +2.5(1.0)%, and the upper critical field Hc2 remains unchanged within uncertainty. The skyrmion phase also changes little under pressure; its largest T extent varies from Tc − 2.5(5) K at ambient pressure to Tc − 3.0(5) K at 5 kbar, and its location in the phase diagram follows the pressure-driven shift of Tc. The weak pressure dependences of the critical magnetic fields and skyrmion phase contrast strongly with much stronger pressure-driven changes reported from previous quasihydrostatic pressure studies. Taking into account the present results and those of other uniaxial pressure data, we suggest that the results of previous quasihydrostatic pressure studies were influenced by inadvertent directional stress pressure components. Overall, our study represents a high-pressure study of the chiral magnetism in Cu2OSeO3 under the most hydrostatic high-pressure conditions to date and serves also as a salient reminder of the sensitivity of chiral magnets to deviations from hydrostaticity in quasihydrostatic high-pressure studies.