Record‐Breaking Magnetoresistance at the Edge of a Microflake of Natural Graphite

Placing several electrodes at the edge of a micrometer-sized Sri Lankan natural graphite sample at distances comparable to the size of the internal crystalline regions, record values for the change of the resistance with magnetic field are found. At low temperatures and at B similar to 21 T, the magnetoresistance (MR) reaches approximate to 107 %. The MR values exceed by far all earlier reported ones for graphite and they are comparable or even larger (at T > 50 K) than the largest reported in solids including the Weyl semimetals. The origin of this large MR lies in the existence of highly conducting 2D interfaces aligned parallel to the graphene planes.