The specific heat cp and magnetization of single crystal hexagonal manganites of the type Yb1-xCa xMnO3 (x=0, 0.05, and 0.10) were measured in a wide temperature range as a function of magnetic field. Antiferromagnetic ordering of the Mn sublattice occurs at TN 83 K. Ca doping has surprisingly minimal effect on the magnetic properties. At low temperature (∼3.5 K), all compounds show ferromagnetic (FM) ordering in the basal plane attributed to Yb in site 2a. For low fields applied along the c direction, Yb spin reorientation occurs and FM ordering disappears. cp shows a broad maximum centered at the temperature ∼6 K that is consistent with a Schottky anomaly related to the Zeeman splitting of the Yb moments due to Mn molecular field. In the field of 30 kOe, the re-entrant FM transition takes place with Yb ions in sites 2a and 4b.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)