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

TL;DR

This study investigates LK-99-like samples, revealing ferromagnetic and insulating behaviors at room temperature, with some samples exhibiting partial levitation, challenging previous claims of superconductivity.

Contribution

The paper provides systematic magnetization and transport measurements on LK-99-like samples, demonstrating coexistence of ferromagnetic and diamagnetic signals and insulating behavior at room temperature.

Findings

Coexistence of ferromagnetic and diamagnetic signals in samples

Insulating behavior with increasing resistivity at lower temperatures

Half-levitation observed in some samples under magnetic influence

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 (Pb$_{10-x}$Cu$_x$(PO$_4$)$_6$O, or called LK-99) [1-3]. 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.