The magnetic and thermal properties of some Cr-B phases at low temperatures ☆

Abstract Investigations of the magnetic and thermal properties of CrB 2 , CrB and Cr 5 B 3 were performed over wide ranges of temperature and of magnetic field. The temperature dependences of the magnetic susceptibilities of CrB 2 , CrB and Cr 5 B 3 proved to be very similar, showing a marked enhancement of the susceptibility at low temperatures. No saturation of the magnetic moment was observed up to 90 kOe. Magnetocaloric effect measurements were performed for all the phases under investigation. In the temperature range 20 – 77 K and in fields up to 80 kOe the sign of the magnetocaloric effect turned out to be negative, as expected for antiferromagnetic phases. Specific heat measurements at about T N showed very small changes in the magnetic part of the entropy compared with those predicted by the local moment model ( S m = Rln (2 J + 1)). All the experimental data on magnetic and thermal properties of Cr-B phases at low temperatures could be related to the model of itinerant-type antiferromagnetism.