Character of magnetic excitations in a quasi-one-dimensional antiferromagnet near the quantum critical points: Impact on magneto-acoustic properties

Magnetocaloric effect in two-dimensional spin-1/2 antiferromagnets

The magnetocaloric effect is studied at the transition to saturation in the antiferromagnetic spin-1/2 Heisenberg model on the simplest two-dimensional lattices, namely the square and the triangular lattice. Numerical results are presented for the entropy which are consistent with identical universal properties. However, the absolute values of the entropy are bigger on the geometrically frustrated triangular lattice than on the non-frustrated square lattice, indicating that frustration improves the magnetocaloric properties.

自旋1/2 Fisher超交换反铁磁体中的逆磁热效应

Inverse magnetocaloric effect in the spin-1/2 Fisher's super-exchange antiferromagnet

本文精确计算自旋1/2 Fisher超交换反铁磁体的等温熵变与绝热温变，揭示二级相变附近显著逆磁热效应的温度区间及其与零温临界磁场的关系。

Magnetization and Magnetoscrition of van Vleck antiferromagnets with magnetic anisotropy of "easy-plane" type

The theoretical description of quantum phase transition, induced by the external magnetic field, into antiferromagnetic state in the van Vleck - singlet - magnet with a single-ion anisotropy of "easy-plane" type and ion spin S=1 is proposed. It is shown that the spin polarization of the ground non-degenerated state proves to be the order parameter of such a transition and that the Landau thermodynamic approach can be employed for its (transition) description. The magnetic properties which include the field behavior of the magnetization and magnetic susceptibility of the antiferromagnetic phase…

Magnetocaloric properties of a frustrated Blume-Capel antiferromagnet

Low-temperature magnetization processes and magnetocaloric properties of a geometrically frustrated spin-1 Blume-Capel model on a triangular lattice are studied by Monte Carlo simulations. The model is found to display qualitatively different behavior depending on the sign of the single-ion anisotropy D. For positive values of D we observe two magnetization plateaus, similar to the spin-1/2 Ising antiferromagnet, and negative isothermal entropy changes for any field intensity. For a range of small negative values of D there are four magnetization plateaus and the entropy changes can be either …

反铁磁合成材料中自旋波的单向性

Unidirectionality of spin waves in Synthetic Antiferromagnets

研究通过实验和建模揭示了反铁磁合成材料中自旋波的频率非对称性，展示了在特定波矢条件下，层间偶极相互作用导致自旋波单向能量传输的特性。