Ferromagnetic half levitation of LK-99-like synthetic samples

2023/08/06 by Kaizhen Guo, Yuan Li, Shuang Jia · 5 voices · 2 citations
Physics and Astronomy · Earth and Planetary Sciences · Materials Science · #Advanced Condensed Matter Physics #High-pressure geophysics and materials #Magnetic and transport properties of perovskites and related materials

paper · pdf · doi:10.1007/s11433-023-2201-9

Abstract

We successfully synthesized polycrystalline LK-99-like ceramic samples with a solid-state-sintering method. Powder X-ray diffraction shows that the main contents are \mathrmPb_10-xCu_x(PO₄)₆O and Cu₂S, consistent with recent reports [arXiv:2307.12037; arXiv:2308.01192]. In some small flaky fragments, we successfully observed ``half levitation'' atop a \mathrmNd₂Fe₁₄B 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. The precise chemical composition and the physics behind the ferromagnetic component remain outstanding questions to be addressed in future research.

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Discussions

• Ferromagnetic half levitation of LK-99-like synthetic samples [hn, 339 points, 314 comments]
• Hopes for a room temperature superconductor crushed on the all-too-familiar shores of ferromagnetism. 🧪 https://arxiv.org/abs/2308.03110 [bsky, 25 points, 1 comments]
• LK-99でしたら、報告された現象は超伝導でなくても説明できる＋超伝導を示す他の証拠がない、ってことで、これもまた勘違いで落着したようです。 arxiv.org/abs/2308.03110 [bsky, 3 points, 0 comments]
• group at Peking university says “no superconductor, hate to spoil your fun” https://arxiv.org/abs/2308.03110 [bsky, 3 points, 0 comments]
• 중국 북경대 그룹에서는 강자성에 의한 현상으로 설명하고 있는데 (약하다고는 하지만) 강자성을 보통 보이지 않는 물질들의 조합 아니었나? 🤔… [bsky, 1 points, 0 comments]

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