Magnetic properties of the singlet antiferromagnet KTb ( WO 4 ) 2

• Published in: Low temperature physics (Woodbury, N.Y.) N.Y.), 2006-01, Vol.32 (1), p.68-76
• Main Authors: Loginov, A. A., Khatsko, E. N., Cherny, A. S., Baumer, B. N., Rykova, A. I., Kalinin, P. S., Sulpis, A.
• Format: Article
• Language: English
• ISSN: 1063-777X; 1090-6517
• DOI: 10.1063/1.2161931

X-ray studies of the magnet KTb ( WO 4 ) 2 have shown that this compound belongs to the monoclinic class C 2 ∕ c with a chain structure. The susceptibility and magnetization of KTb ( WO 4 ) 2 single crystals are investigated experimentally in the temperature region 0.4–100 K and at magnetic fields up to 2 T. The angular dependence of the susceptibility shows that at low temperatures a purely Ising anisotropy is realized in this compound: there exists but one component of the moment, along the b axis. The temperature dependence of the susceptibility has a maximum at T = 1.2 K , and the M ( H ) curve obtained at 0.5 K exhibits substantial nonlinearity at low fields, as is characteristic of an ordered state. Analysis of the experimental data in the mean field approximation suggests that this state is a singlet Ising antiferromagnet with T N ≈ 0.7 K , a value determined from the susceptibility data. At extremely low temperatures a collinear antiferromagnetic structure with equivalent sublattices is realized in the sample, according to estimates made. The high-temperature behavior of the susceptibility is evidence of the presence of an excited quasi-doublet in the vicinity of 35 K.