NEW ANTIFERROMAGNETIC INSULATOR SUPERLATTICES - STRUCTURAL AND MAGNETIC CHARACTERIZATION OF (FEF2)M(COF2)N

High-quality antiferromagnetic (AF) superlattices (FeF2)m(CoF2)n, as judged from high-resolution x-ray diffraction (HRXD), were grown on (001) ZnF2 substrates. Using HRXD, the thermal-expansion coefficient [001](T) vs T was measured. While two shifted AF anomalies are seen for (m,n)=(25,30), only one is observed for (m,n)=(19,6). Comparison of [001](T) in the two superlattices with that of FeF2 and CoF2 indicates that a significant redistribution of the magnetic entropy occurs. © 1990 The American Physical Society.