Effects Of Interlayer And Bi-Quadratic Exchange Coupling On Layered Triangular Lattice Antiferromagnets

The magnetic field evolution of ground spin states of the stacked planar triangular antiferromagnet with antiferromagnetic interlayer interaction J(c) is explored using a minimal 3D classical Heisenberg model. A bi-quadratic coupling is also used to mimic the effect of spin fluctuations (Zhitomirsky 2015 J. Phys.: Conf. Ser. 592 012110) which are known to stabilize the magnetization plateau. A single ion anisotropy is included and states with a magnetic field applied in the ab plane and along the c axis are determined. For H parallel to ab-plane, an additional new state, in contrast to 2D model (Zhitomirsky 2015 J. Phys.: Conf. Ser. 592 012110), is obtained with weak interlayer interaction, while the magnetization plateau vanishes at large J(c) and other new states with z components of spins emerge. For H parallel to c-axis, an extra state, compared with 2D model, is obtained with a weak interlayer interaction. When J(c) is large enough, only the state corresponding to the Umbrella phase in 2D model exits.