Mg掺杂对[NH2(CH3)2]Mn1-xMgx(HCOO)3单晶性能的影响

Doping Effect of Mg on the Physics Properties of[NH_2(CH_3)_2]Mn_(1-x)Mg_x(HCOO)_3 Single Crystals

通过水热法合成一系列不同掺杂浓度晶体[NH_2(CH_3)_2]Mn_(1-x)Mg_x(HCOO)_3(0≤x≤0.5),并对其进行X射线粉末衍射、紫外可见光谱、傅里叶变化红外光谱(FTIR)、热重等表征分析。结果表明:制备晶体的结晶性能好,透明度高,晶体为三方晶系,空间群为R-3c(167);Mg^(2+)的掺入加剧了Mn-O_6八面体的畸变,导致晶体的晶格参数发生明显变化;晶体结构框架在120℃时开始坍塌,在230℃时,甲酸根分解挥发。光学测试结果表明:晶体的禁带宽度为3.73 eV,Mg掺杂对禁带宽度没有影响。磁性测试结果表明:当测试温度范围为5~300K时,随着掺杂量增加,样品的奈耳温度(T_N)变小,当掺杂量为0.5,反铁磁转变消失。

A series of crystals with different doping concentrations of [NH2（CH3）2]Mn（1-x）Mgx（HCOO）3（0 ≤ x ≤ 0.5）were synthesized by hydrothermal method,and characterization analysis was made on the crystals by X ray powder diffraction, UV-Vis spectrum,Fourier transform infrared spectroscopy（FTIR）,and thermogravimetry.The experimental results show that the obtained crystals are of good crystallization property,high transparency,and trigonal system with space group R-3c（167）;the distortion of the Mn-O6 octahedra is intensified by the incorporation of Mg^2＋,causing the lattice parameter of the crystals to change obviously;the structure framework of the crystals begin to collapse at the temperature of 120℃,and the formate is decomposed and volatilized at the temperature 230℃.The optical measurement results show that the energy gap of the crystals is 3.73 eV,and the doping of Mg has no influence on the energy gap.The magnetic measurement results show that Neel temperature（TN）of the samples decreases as the doping content increases at the test temperature ranging from 5 to 300 K,and the antiferromagnetism is transformed and disappears when the doping content reaches 0.5.