Coupled magnetic and structural phase transitions in the antiferromagnetic polar metal Pb 2 Co Os O 6 under pressure

摘要: ${\mathrm{Pb}}_{2}\mathrm{Co}\mathrm{Os}{\mathrm{O}}_{6}$ is a newly synthesized polar metal in which inversion symmetry broken by the magnetic frustration an antiferromagnetic ordering of Co and Os sublattices. The coupled structural transition occurs at 45 K ambient pressure. Here, we perform transport measurements first-principles calculations to study pressure effects on magnetic/structural ${\mathrm{Pb}}_{2}\mathrm{Co}\mathrm{Os}{\mathrm{O}}_{6}$. Experimentally, monitor resistivity anomaly ${T}_{N}$ under various pressures up 11 GPa cubic anvil cell apparatus. We find that determined from first increases quickly with large slope $d{T}_{N}/dP=+6.8(8)\phantom{\rule{0.28em}{0ex}}\mathrm{K}/\mathrm{GPa}$ for $Pl4\phantom{\rule{0.28em}{0ex}}\mathrm{GPa}$ and, then, much reduced 1.8(4) K/GPa above 4 GPa. Our suggest observed discontinuity $d{T}_{N}/dP$ around may be attributed vanishing moment Pressure substantially reduces completely suppresses it critical value, relieves distortions decrease increasing simultaneously vanish Therefore, pressure, new centrosymmetric state emerges ${\mathrm{Pb}}_{2}\mathrm{Co}\mathrm{Os}{\mathrm{O}}_{6}$, distinct one thus, showing $d{T}_{N}/dP$.