Magnetization easy plane

As shown in fig. 9 for the magnetization at 5 K, the magnetic easy axis is in the plane of the film, and shows a weak four-fold symmetry within the plane. The anisotropy energy... 

The parameters rp and 7J2 are linear combinations of the magnetic modes converted on the representation T5. The fact that below TN the magnetic subsystem of copper metaborate forms an easy-plane weak ferromagnet, twisted below 7] in a spiral, permits to compose rp as a combination of the ferromagnetic modes (1) and (3), and tj2 as a combination of the antiferromagnetic modes (2) and (4). Accordingly II = (Hn, Hn) = (Hx, -Hy). It is necessary to note that in the thermodynamic potential given by Eq. (5) the order parameter responsible for the transition at 7] is not chosen in an explicit form as it was done in our previous paper [8],... 

Figures 1 and 2 show the isotherms obtained from the magnetization measurements at different temperatures for TbFeeCosTi and its hydride, respectively. Unlike TbFenTi, the TbFeeCosTi single crystal exhibits a uniaxial magnetic anisotropy over the entire studied range of temperatures from 4.2 K to Tc. It is show that Fe replacement by Co suppresses easy plane anisotropy completely at Co concentration x = 5.

As can be seen from Fig. 2, hydrogenation induces easy plane anisotropy in TbFeeCosTiH. The [100] direction becomes easy magnetization axis and critical fields are not observed in the field dependences of the magnetization for TbFe6Co5TiH. 

Fe"-Fe " Mixed Valence Single-Chain Magnet Induced by a Twisted Arrangement of Easy-Plane Magnetic Anisotropy... 

Note the ZFS introduces preferred orientations for the spin in zero applied field. For negative D, in axial symmetry, this is along the unique symmetry axis (z), for positive D it is in the plane (xy) perpendicular to this axis, leading to the terms easy axis or easy plane type magnetic anisotropy. Application of an applied field along z separates the states as MsgPH as before e.g. Figure 5.3). 

An important aspect of one-dimensional magnetism is the nature of the magnetic interaction between the spins. It can be isotropic, as described by the spin Hamiltonian Equation (6), or anisotropic. In the axial limit the anisotropy can be of the easy-axis type (Ising anisotropy) or of the easy-plane type (XY anisotropy). The former means that the spins tend to orient parallel to a preferential direction while for the latter they orient in a plane. The physical properties of the chains are strongly influenced by the nature of the anisotropy. ... 

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