Magnetic properties of terbium dihydrides

• Published in: Solid state communications 2009-08, Vol.149 (31), p.1266-1268
• Main Authors: Drulis, H., Hackemer, A., Folcik, L.
• Format: Article
• Language: English
• Subjects: A. Magnetically ordered materials; B. Magnetocaloric effect; C. Thermodynamic properties; Condensed matter: electronic structure, electrical, magnetic, and optical properties; E. Magnetic measurements; Exact sciences and technology; Magnetic phase boundaries (including magnetic transitions, metamagnetism, etc.); Magnetic properties and materials; Magnetically ordered materials: other intrinsic properties; Magnetocaloric effect, magnetic cooling; Physics
• ISSN: 0038-1098; 1879-2766
• DOI: 10.1016/j.ssc.2009.05.016

Magnetization measurements of terbium dihydride samples with different hydrogen concentration, TbH 1.92, TbH 1.99, TbH 2.03 and TbH 2.09, in the temperature range from 1.8 to 300 K and at an applied field of 1 kOe are reported. Two first-order antiferromagnetic transitions have been registered in the narrow temperature range between 15–18 K for all hydride compositions. Isothermal magnetization ( σ ( H ) T = const ) measurements at several temperatures in the vicinity of magnetic transitions have been carried out and used for the magnetic-entropy change, Δ S σ , calculations. The magnetic-entropy changes have negative values, and in an applied magnetic field of 5 T they reach 2.5 J/kg K, which is only about 26% of the Δ S σ ( H ) value expected from thermal measurements. A much larger magnetic field must be applied for terbium hydrides to be used as refrigerant materials for low-temperature needs.