Nonlinear magnetic susceptibility measurements at GPa-level pressures

Abstract

The second nonlinear susceptibility, χ(2), reflects magnetic domain formation. At zero DC field, the temperature dependence of χ(2) can be obtained through that of the third-harmonic AC susceptibility, χ3ω. Generally, the magnitude of χ3ω is at most a few percent of the linear component, χ1ω, connected with the linear susceptibility, χ(0). At GPa-level pressures generated using a diamond anvil cell, the detection of χ3ω becomes more difficult, because of the small amount of measurement sample. We propose an effective method of measuring χ3ω using a superconducting quantum interference device magnetometer and a statistics average technique. The experimental results for an inorganic chiral magnet, Cr1/3NbS2, indicate the efficiency of this technique and demonstrate that magnetic signals of the order of 10-9 emu can be detected. © 2010 IOP Publishing Ltd.