Neutron powder diffraction measurements have been performed on Ce_xNd_{1-x}B_6 (x = 0.5, 0.6, 0.7, and 0.8) solid solutions to determine the type of magnetic order occurring in these compounds as a result of the interplay between magnetic dipole exchange and antiferroquadrupolar interactions. In the Ce-rich range, the sequence of two magnetic phases, with an incommensurate order [k = (1/4 -delta, 1/4 -delta, 1/2)] forming below T N followed by a lock-in--type transition at lower temperature, is quite similar to that reported earlier for Ce_xPr_{1-x} B_6. For x = 0.5, on the other hand, the same antiferromagnetic order as in pure NdB6 first occurs at TN, then coexists with an incommensurate component below the lower transition temperature. These results are in good agreement with previous resistivity measurements and support the idea that Ce and Nd magnetic moments in this system can be relatively decoupled.
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