A Magnetic Structural Study of Tb2Mo2O7, Sr2CrO3F and SrLaCrO4

Abstract

<p> Magnetic susceptibility data indicate that Tb2Mo2O7 undergoes a spin glass transition at 25 K. The crystal structure is consistent with the fully ordered pyrochlore model. Short range order, involving ferromagnetic and antiferromagnetic correlations, is observed down to 8 K by neutron scattering. </p> <p> Sr2Cr03F and SrLaCr04 have the same magnetic structure. The neutron diffraction data are consistent with two different models. In both cases the magnetic cell is √2a and c and the magnetic moments lie out of the plane. However, in one model the in-plane projection is canted and in the other it is colinear. Sr2Cr03F has a Tc value of 132(2) K and a susceptibility maximum at 280 K. SrLaCr04 has a Tc value of approximately 200 K and a susceptibility maximum near 400 K. The critical· exponent β for Sr2Cr03F is 0.26(4). The (100) magnetic reflection of both SrLaCr04 and Sr2Cr03F shows short range order correlations above Tc. </p>