Pulsed Critical Field Measurements in Magnetic Systems

Abstract

Pulsed field magnetic moment measurements in several magnetic systems are briefly summarized. Particularly high sensitivity is attained for systems which exhibit a nonlinear variation of magnetization versus applied field, e.g., ``spin‐flop.'' Changes of magnetization as small as 0.1 gauss could be observed with applied fields of over 100 kgauss under favorable circumstances. Critical fields for Cr₂O₃ and (Cr₂O₃)_0.9·(Al₂O₃)_0.1 from 4.2°K to about 0.95 T_N and the corresponding calculated values of (2λK)^½ are presented, where λ is the exchange constant and K is the anisotropy energy. The values of (2λK)^½ agree with earlier antiferromagnetic resonance measurements in similar crystals. Results of measurements in antiferromagnetic MnF₂, CoF₂, and FeTiO₃, and in metamagnetic FeCl₂ and CoCl₂ are briefly discussed. Application of the method to paramagnets is also indicated.