Magnetization and phase diagram of EuTe/PbTe superlattices

The magnetic state of anti ferro magnetic EuTe/PbTe superlattices with 3 or 5 EuTe (1 1 1)-monolayers sandwiched between 24 or 25 PbTe (1 1 1)-monolayers are investigated by mean-field analysis (MFA) and compared with SQUID-magnetization experiments for in-plane magnetic fields up to 7 T and temperatures between 2 and 13 K. The EuTe-stacks are treated as isolated few-monolayer antiferromagnets compressively strained due to the 2% lattice mismatch to PbTe. The evaluation of critical magnetic fields at the various magnetic phase boundaries (anti ferromagnetic, spin-flop, paramagnetic) and of the Neel-temperatures allows an independent determination of the intra- and inter-layer exchange constants. (c) 2004 Elsevier B.V. All rights reserved.