Ferromagnetic and insulating behavior in both half magnetic levitation and non-levitation LK-99 like samples

Abstract Finding materials exhibiting superconductivity at room temperature has long been one of the ultimate goals in physics and material science. Recently, room-temperature superconducting properties have been claimed in a copper substituted lead phosphate apatite (Pb10-xCux(PO4)6O, or called LK-99) (Lee et al. in J. Korean Cryst. Growth Cryst. Technol. 33:61, 2023; Lee et al. in The first room-temperature ambient-pressure superconductor, 2023; Lee et al. in Superconductor Pb10-xCux(PO4)6O showing levitation at room temperature and atmospheric pressure and mechanism, 2023). Using a similar approach, we have prepared LK-99 like samples and confirmed the half-levitation behaviors in some small specimens under the influence of a magnet at room temperature. To examine the magnetic properties of our samples, we have performed systematic magnetization measurements on the as-grown LK-99 like samples, including the half-levitated and non-levitated samples. The magnetization measurements show the coexistence of soft-ferromagnetic and diamagnetic signals in both half-levitated and non-levitated samples. The electrical transport measurements on the as-grown LK-99 like samples including both half-levitated and non-levitated samples show an insulating behavior characterized by the increasing resistivity with the decreasing temperature.