Speaker
Description
$\mathrm{LiFePO}_4$ (LFPO) is an archetypical and well-known cathode material [1] for rechargeable Li-ion batteries. However, its quasi-one-dimensional (Q1D) structure (see Figure) along with the Fe ions, LFPO also displays interesting low-temperature magnetic properties [2]. At ambient pressure LFPO display an antiferromagnetic (AFM) spin order below $T_N = 53\;\mathrm{K}$ and neutron scattering [3-5] have characterized that LFPO orders in a canted AFM ground state below $T_N$. Our team has previously utilized muon spin rotation ($\mu^+$SR) to investigate both magnetic order as well as Li-ion diffusion in LFPO [6] as well as nano-structured LFPO [7,8] and related compounds [9-11]. In this initial study we make use of high-pressure $\mu^+$SR to investigate effects on the low-T magnetic order. We find a clear decrease in $T_N$ at $p = 20\; \mathrm{kbar}$ and we can estimate that a complete suppression of magnetic order should appear around $p_c \approx 300\; \mathrm{kbar}$.
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[4] Li, et al., Phys. Rev. B 73, 024410 (2006)
[5] Toft-Petersen, et al., Phys. Rev. B 92, 024404 (2015)
[6] Sugiyama, Mansson, et al., Phys. Rev. B 84, 054430 (2011)
[7] Benedek, et al., Sustainable Energy & Fuels [RSC] 3, 508-513 (2019)
[8] Bendek, et al., ACS Applied Materials & Interfaces 12, 14, 16243 (2020)
[9] Ofer, et al., Phys. Proc. 30, 160 (2012)
[10] Sugiyama, et al., Physical Review Research 2, 033161 (2020)
[11] Forslund, et al., arXiv:2111.11941 (2021)
