Distant neighbors exchange interactions in Cd1-xMnxTe

From magnetization measurements in bulk samples of Cd1 - xMnxTe (x less than or equal to 3.6%), at T = 20 mK, three new antiferromagnetic exchange constants, beyond the nearest-neighbors J(1) = - 6. 1 +/- 0.3 K, were measured. In order of decreasing strength, they are J((2)) = - 0.39 +/- 0.02, J((3)) = - 0.18 +/- 0.01 and J((4)) = - 0.06 +/- 0.01 K. Comparison of the data with theoretical simulations based on the cluster model with random distribution, made so far, has established that: (a) J((3)) corresponds unequivocally to the third-neighbors constant J(3); (b) similar to the case of Zn-compounds (V. Bindilatti et al., Phys. Rev. Lett. 80 (1998) 5425), there is strong evidence that J((9)) corresponds to J(4) contrary to theoretical predictions. (C) 2000 Elsevier Science B.V. All rights reserved.