Quantum phase transition: Van Vleck antiferromagnet in a magnetic field

• Дата: 2008
• Автори: Ivanova, I.M., Kalita, V.M., Pashkov, V.O., Loktev, V.M.
• Формат: Стаття
• Мова: English
• Опубліковано: Інститут фізики конденсованих систем НАН України 2008
• Назва видання: Condensed Matter Physics
• Онлайн доступ: http://dspace.nbuv.gov.ua/handle/123456789/119337
• Назва журналу: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Цитувати: Quantum phase transition: Van Vleck antiferromagnet in a magnetic field / I.M. Ivanova, V.M. Kalita, V.O. Pashkov, V.M. Loktev // Condensed Matter Physics. — 2008. — Т. 11, № 3(55). — С. 509-522. — Бібліогр.: 42 назв. — англ.

Theoretical description of magnetic properties of antiferromagnetic state, induced by the longitudinal magnetic eld, in the Van Vleck singlet magnet with single-ion anisotropy of easy-plane type and ion spin S = 1 is proposed. It is shown that the quantum phase transition to the antiferromagnetic state is connected with the spontaneous appearance of spin polarization in the easy plane. Spin polarization of the ground nondegenerated state proves to be the order parameter of such a transition and the Landau thermodynamic approach can be employed for its (transition) description. The magnetic properties which include the eld behavior of magnetization and magnetic susceptibility of the antiferromagnetic phase in the elds of different directions are studied. An attempt is made to qualitatively compare the obtained results with the available experimental data.