The magnetic susceptibility of an MnO single crystal

2014 The magnetic susceptibility of an MnO single crystal grown by flame fusion was found to be similar to the powder material ; however, the magnetic field dependence of the susceptibility was larger than the dependence for the powder and in addition extended into the paramagnetic region. LE JOURNAL DE PHYSIQUE ET LE RADIUM TOME 20, FÉVRIER-MAns 1959, Magnetic susceptibility measurements of MnO powder made by Bizette, Squires and Tsaï [1] showed strong magnetic field dependence of the susceptibility below 116 oK (the Néel temperature), an effect which was interpreted by Néel [2] and also Van Vleck [3] as one of the characteristics of antiferromagnetism. We have made measurements on a small pièce of MnO single crystal which weighed 68.7 milligrams. The specimen was grown by Prof. W. H. FIG. 1. Magnetic susceptibility as a function of temperature. The dotted line for H = 0 is the projection of the slopes found in fig. 2. Bauer of Rutgers University by the flame fusion method and made available to us by the M. J. T. Lincoln Laboratory (1). Because of the small size of the sample we were not able to determine the chemical composition but an X-ray Laue photo(1) We wish to thank Dr. S. Foner for sending us this specimen, and for the information that powder x-ray data on the original boule showed that if higher oxide were present they were less than a few per cent, graph by Miss S. W. Greenwald showed that the sample is a single crystal. The agreement of its magnetic properties with powder data, both in magnitude and temperature dependence, lead us to believe that the composition is nearly stoichiometric. The magnetic measurements were made by a force method [4]. Preliminary data taken in the antiferromagnetic region indicated that the susceptibility was isotropic. Fig. 1 and fig. 2 show the FIG. 2. The magnetic susceptibility in fields 4 100 to 8 860 Oe. susceptibility plotted as a function of temperature and in fields up to 8 500 oersteds. The magnetic field was along a [110] direction and the vertical rotation axis was roughly a [110] direction. After these initial measurements the sample was annealed in helium in 200 OC for several hours and measured with the same orientation in fields up Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphysrad:01959002002-3042400