Published online by Cambridge University Press: 28 February 2011
X-ray absorption measurements have been made on powder samples of YBa2Cu3O7 and La1.85sr0.15CuO4 oriented in a magnetic field. Measurements made at the Cu K edge with the x-ray polarization oriented perpendicular and parallel to the c-axis show distinct differences for both materials, indicating a strong anisotropy of the electronic states about the Cu atoms. The Y edge measurements show a much smaller anisotropy as expected due to its more symmetric environment. Preliminary analysis indicates these measurements should be useful in choosing between the conflicting interpretations of the near edge structure in these materials.