Ferromagnetic half levitation of LK-99-like synthetic samples
Ferromagnetic half levitation of LK-99-like synthetic samples
Kaizhen Guo, Yuan Li, Shuang Jia
AbstractWe successfully synthesized polycrystalline LK-99-like ceramic samples with a solid-state-sintering method. Powder X-ray diffraction shows that the main contents are $\mathrm{Pb_{10-x}Cu_x(PO_4)_6O}$ and $\mathrm{Cu_2S}$, consistent with recent reports [arXiv:2307.12037; arXiv:2308.01192]. In some small flaky fragments, we successfully observed ``half levitation'' atop a $\mathrm{Nd_2Fe_{14}B}$ magnet. Using magnetization measurements on such small pieces, as well as on a large piece which does not exhibit the half levitation, we show that the samples ubiquitously contain weak yet definitive soft ferromagnetic components. We argue that, together with the pronounced shape anisotropy of the small fragments, the soft ferromagnetism is sufficient to explain the observed half levitation in strong vertical magnetic fields. Our measurements do not indicate the presence of the Meissner effect, nor zero resistance, in our samples, leading us to believe that our samples do not exhibit superconductivity.