报告了对R5Pt2In4(R=Tb-Tm)进行的中子粉末衍射测量的结果。化合物以Lu5Ni2In4型正交晶体结构结晶,稀土原子占据三个不同的亚晶格。在低温下,对于R=Tb,稀土磁矩低于等于105、93、28、12和3.8K的临界温度,Dy,Ho,呃和Tm,分别。随着温度的降低,2a和4g2位点处的稀土磁矩优先排序,而时刻在4g1站点顺序在较低的温度。沿c轴的铁磁顺序,由传播矢量k1=[0,0,0]描述,在居里温度以下的Tb5Pt2In4中发展(TC=108K)。在较低的温度下,在ab平面中出现反铁磁成分。该成分与晶体结构(k2=[0,0.66,1/2])不相称,但是随着温度的降低,它变成了一个相称的(k3=[0,0,½])。沿c轴的反铁磁顺序,用k4=[½,0,0],在低于Néel温度的Dy5Pt2In4中发现(TN=93K)。与k4相关的分量在80K以下消失,并且磁结构转变为由k1=[0,0,0]描述的铁/亚铁磁结构。温度的进一步降低导致沿ab平面在10K(k2=[0,0.45,1/2])以下出现不相称的反铁磁成分,最终变成一个相称的(k5=[0,½,½]).在Ho5Pt2In4中,一种正弦调制的磁结构,其力矩平行于c轴(k6=[1/3,0,0])在28K以下观察到。随着温度的降低,新组件,与k1=[0,0,0](bc平面)和k4=[½,0,0](c轴),出现。两个顺序共存-在ab平面(k1=[0,0,0])和沿b轴具有力矩的调制顺序(k7=[kx,0,0])-在Er5Pt2In4中发现低于12K。降低温度会导致k1相关分量到另一个分量的阶次转换,磁矩仍然约束在ab平面上,并且传播矢量的值保持不变(即k1=[0,0,0])。Tm5Pt2In4在TN=4.1K以下反铁磁阶数。Thulium磁矩位于ab平面中,而磁性结构由k5=[0,1/2,½].磁矩的方向取决于所涉及的稀土元素,并表明与晶体电场相互作用导致的单离子各向异性的影响。
Results of the neutron powder diffraction measurements carried out for R5Pt2In4 (R = Tb-Tm) are reported. The compounds crystallize in an orthorhombic crystal structure of the Lu5Ni2In4-type with the rare earth atoms occupying three different sublattices. Neutron diffraction data reveal that at low temperatures the rare earth magnetic moments order below the critical temperature equal to 105, 93, 28, 12 and 3.8 K for R = Tb, Dy, Ho, Er and Tm, respectively. With decreasing temperature the rare earth magnetic moments at the 2a and 4g2 sites order first, while the moments at the 4g1 site order at lower temperatures. Ferrimagnetic order along the c axis, described by the propagation vector k1 = [0, 0, 0], develops in Tb5Pt2In4 below the Curie temperature (TC = 105 K). At lower temperatures, an antiferromagnetic component in the ab plane appears. The component is incommensurate with the crystal structure (k2 = [0, 0.66, ½]), but it turns into a commensurate one (k3 = [0, 0, ½]) with decreasing temperature. Antiferromagnetic order along the c axis, described by k4 = [½, 0, 0], is found in Dy5Pt2In4 below the Néel temperature (TN = 93 K). The k4-related component disappears below 80 K and the magnetic structure transforms into a ferro/ferrimagnetic one described by k1 = [0, 0, 0]. Further decrease in temperature leads to the appearance of an incommensurate antiferromagnetic component within the ab plane below 10 K (k2 = [0, 0.45, ½]), which finally turns into a commensurate one (k5 = [0, ½, ½]). In Ho5Pt2In4, a sine-modulated magnetic structure with moments parallel to the c axis (k6 = [⅓,0,0]) is observed below 28 K. With a decrease in temperature, new components, related to k1 = [0, 0, 0] (bc plane) and k4 = [½, 0, 0] (c axis), appear. The coexistence of two orderings - in the ab plane (k1 = [0, 0, 0]) and a modulated one with moments along the b axis (k7 = [kx, 0, 0]) - is found in Er5Pt2In4 below 12 K. Decreasing temperature leads to the order-order transformation of the k1-related component to another one with magnetic moments still constrained to the ab plane and preserved value of the propagation vector (i.e. k1 = [0, 0, 0]). Tm5Pt2In4 orders antiferromagnetically below TN = 3.8 K. Thulium magnetic moments lie in the ab plane, while the magnetic structure is described by k5 = [0, ½ , ½]. The direction of magnetic moments depends on the rare earth element involved and indicates an influence of single ion anisotropy resulting from interaction with the crystalline electric field.