共查询到19条相似文献,搜索用时 218 毫秒
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在一些磁性材料内, 磁性离子间交换作用和磁性离子的自旋涨落对材料磁性有影响. 本文根据磁比热实验值确定了晶场参数后, 利用包含自旋涨落的交换作用有效场Hm= n0 (1 + γ T + β eω T)M, 计算了PrNi2晶体晶场能级的Zeeman劈裂. 在温度为3.8 K ≤T≤ 30 K范围内, 计算了该晶体多晶磁矩随外磁场的变化, 以及外磁场H=5000 Oe时磁化率倒数随温度的变化, 计算结果和实验值符合较好. 当外磁场在0–50000 Oe时, 计算的该晶体的磁熵变与已有文献的理论结果相似. 计算结果说明, 提出的包含自旋涨落的交换作用有效场不仅适合亚铁磁性晶体, 而且也适合顺磁性晶体.
关键词:
2')" href="#">PrNi2
磁比热
交换作用有效场
磁矩
磁熵变 相似文献
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应用不可约张量理论构造了三角对称晶场中3d2/3d8态离子的45阶可完全对角化的微扰哈密顿矩阵,在考虑了以前工作中被忽略的自旋-自旋耦合作用的基础上计算了CsNiCl3晶体和CsNiCl3:Mg2+晶体的基态能级、晶体结构、零场分裂参量和Jahn-Teller效应,研究了掺入Mg2+对CsNiCl3晶体的光谱、零场分裂参量及Jahn-Teller效应的影响和自旋单重态对基态能级的贡献,发现掺杂使得晶体结构产生畸变,从而改变晶体光谱的精细结构和零场分裂参量,不改变Jahn-Teller效应的分裂规律但改变分裂的大小.
关键词:
基态能级
掺杂
零场分裂
自旋-自旋耦合 相似文献
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采用了中间场耦合图像,考虑了以前研究中被忽略的SS (spin-spin)磁相互作用以及SOO (spin-other-orbit)磁相互作用,利用完全对角化方法,研究了3d2态离子在三角对称 (C3v, D3, D3d)晶体中自旋哈密顿(SH)参量的微观起源.发现自旋哈密顿参量 (包括零场分裂参量D和g因子g∥,g⊥)来自四种耦合机理:(1)SO (spin-orbit)耦合机理; (2) SS耦合机理;(3)SOO
关键词:
自旋哈密顿参量
2态离子')" href="#">3d2态离子
三角对称晶场
SS与SOO作用
SO-SS-SOO联合作用机理 相似文献
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本文在晶场理论的基础上,考虑了Cu2+-Cu2+离子间的交换作用后,得到了(φ4As) CuCl3晶体中Cu2--Cu2-离子对的跃迁能级,g-因子和零场分裂,计算结果与实验符合较好。 相似文献
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应用不可约张量理论构造了三角对称晶场中3d2/3d8态离子的45阶可完全对角化的微扰哈密顿矩阵,研究了CsNiCl3晶体的光谱精细结构、晶体结构、零场分裂参量、Jahn-Telller效应以及自旋单重态对Ni2+离子基态能级的影响,理论与实验相符合.在此基础上,进一步研究了以前工作中被忽略的自旋-自旋耦合作用和Trees修正对CsNiCl3晶体的光谱精细结构和零场分裂参量的影响,发现有四种机理会影响零场分裂参量:1)自旋-轨道耦合机理,2)自旋-自旋耦合机理;3)自旋-轨道与自旋-自旋联合耦合机理;4)自旋-轨道与Trees修正联合耦合机理,其中自旋-轨道耦合机理是最主要的,其他三种机理也是不可忽略的.
关键词:
基态能级
精细结构
零场分裂
自旋-自旋耦合 相似文献
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采用交换相互作用的分子场理论模型对金属间化合物HoMn6Sn6的自旋重取向相变进行了研究. 从理论上计算了HoMn6Sn6的易磁化方向以及Ho和Mn离子磁矩与c轴夹角随温度的变化. 基于单离子模型计算了Ho离子的一阶和二阶磁晶各向异性常数K1R和K2R随温度的变化. 研究表明,为了很好描述该化合物的自旋重取向相变,必须考虑Ho离子的四阶晶场项及相应的二阶磁晶各向异性常数K2R,K2R与K1R和Mn离子磁晶各向异性常数K1t之间的相互竞争是导致HoMn6Sn6自旋重取向相变的重要因素.
关键词:
稀土-过渡族金属间化合物
自旋重取向
磁晶各向异性 相似文献
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By taking into account slight interactions, i.e. spin-spin, spin-other-orbit and orbit-orbit interactions, in addition to
spin-orbit interaction, the zero-field splitting of 4
T
2 state for 3d3 ions at tetragonal symmetry has been studied. The convergence of the approximation perturbation formula of 4
T
2 state for 3d3 ions at tetragonal symmetry has been investigated, and the contributions to zero-field splitting arising from magnetic interaction
and tetragonal crystal field are discussed. It is found that there exists combined mechanism between magnetic interactions
and tetragonal crystal field.
相似文献
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本文计算了顺磁物质CeF3因Ce3+离子从基态能级4f至5d的电偶极跃迁产生的Fara-day旋转。讨论晶场对Ce+3离子4f和5d能级的影响,通过唯象地引入一个与磁化强度M成正比的“附加磁场”Hm=λM,由此获得4f离子在外加磁场和“附加磁场”的共同作用下的一级Zeeman分裂。经劈裂后的两个子能级上各自产生左、右圆偏振光激发的电偶极跃迁,导致磁光Faraday效应。对于波长为0.6328μm的入射光,在60—300
关键词: 相似文献
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R. Yu. Babkin K. V. Lamonova S. M. Orel S. G. Ovchinnikov Yu. G. Pashkevich 《JETP Letters》2014,99(8):476-480
Changes in the spin state of Co3+ ions in LaCoO3 and GdCoO3 compounds are studied through the use of the temperature dependence of the magnetic susceptibility and the modified crystal field theory. It is shown that the spin subsystem of Co3+ ions in LaCoO3 and GdCoO3 undergoes the spin-crossover type transition between the high-spin (S = 2) and low-spin (S = 0) states without any contribution of the intermediate-spin state (S = 1). 相似文献
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A.S. Aleksandrovsky A.V. Malakhovskii V.N. Zabluda A.I. Zaitsev A.V. Zamkov 《Journal of Physics and Chemistry of Solids》2006,67(8):1908-1912
Optical absorption, luminescence, magnetic circular dichroism and Faraday rotation spectra of Sr0.95Eu0.05B4O7 single crystals are studied. The crystal field parameter for europium ions is found to be equal to 790 cm−1. Excitation spectrum of luminescence strongly differs from that of low-doped polycrystalline strontium tetraborate. The Verdet constant in the ultraviolet is comparable to that of terbium gallium garnet in the visible. 相似文献
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Effects of exchange interaction and spin-fluctuation on the magnetic and magneto-optic properties of NdF3 下载免费PDF全文
The exchange interaction between the electrons in the different magnetic ions and the spin-fluctuation of the magnetic ions exist in the paramagnetic media NdF3. The exchange interaction between the electrons in the different magnetic ions may be equivalent to an effective field Hin that is in direct proportion to the magnetization M. The spin-fluctuation of the magnetic ions leads the coefficient of the effective field to vary with temperature. The effective field is given as Hin = -(0.75 + 0.22T) × 10^-5M in NdF3. When the secondary crystal field effect is taken into account, the magnetic susceptibility and Verdet constant are calculated for NdF3 by means of the effective field Hin and the applied field He. The calculated results are in agreement with the measured ones. 相似文献
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FePS3 is a layered antiferromagnet (T
N=123 K) with a marked Ising anisotropy in magnetic properties. The anisotropy arises from the combined effect of the trigonal
distortion from octahedral symmetry and spin-orbit coupling on the orbitally degenerate5
T
2g
ground state of the Fe2+ ion. The anisotropic paramagnetic susceptibilities are interpreted in terms of the zero field Hamiltonian, ℋ=Σi [δ(L
iz
2
−2)+|λ|L
i
.S
i
]−Σ
ij
J
ij
S
i
.S
j
. The crystal field trigonal distortion parameter Δ, the spin-orbit coupling λ and the isotropic Heisenberg exchange,J
ij, were evaluated from an analysis of the high temperature paramagnetic susceptibility data using the Correlated Effective
Field (CEF) theory for many-body magnetism developed by Lines. Good agreement with experiment were obtained for Δ/k=215.5 K; λ/k=166.5 K;J
nn
k=27.7 K; andJ
nnn
k=−2.3 K. Using these values of the crystal field and exchange parameters the CEF predicts aT
N=122 K for FePS3, which is remarkably close to the observed value of theT
N. The accuracy of the CEF approximation was also ascertained by comparing the calculated susceptibilities in the CEF with
the experimental susceptibility for the isotropic Heisenberg layered antiferromagnet MnPS3, for which the high temperature series expansion susceptibility is available. 相似文献
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利用MPMS-7(magnetic property measurement system)型超导量子磁强计对垂直布里奇曼法生长的Hg0.89Mn0.11Te晶片磁化强度变化规律进行了测量.试验采用了两种不同的外场和冷却条件.首先在5 K恒温下,-5200到5200 kA/m范围内改变磁场强度进行了测定.然后维持800 kA/m恒定磁场,分别在有场冷却和无场冷却条件下,从5到300 K范围内改变温度,研究了变温条件下的磁化特性.并采用分子场近似模型,用类布里渊函数,最小二乘法对磁化强度随磁场强度变化的实验结果进行拟合和分析,结果表明,Mn2+离子之间存在反铁磁相互作用.磁化率和温度关系分析表明:在测试范围内Hg0.89Mn0.11Te是单一的顺磁相,在高温区磁化率和温度服从居里-万斯定律,呈线性关系,低于40 K时,磁化率和温度的关系偏离居里-万斯定律,表现出顺磁增强现象.
关键词:
0.89Mn0.11Te')" href="#">Hg0.89Mn0.11Te
磁化强度
磁化率
类布里渊函数 相似文献
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提出了解释掺杂离子局域结构畸变的配体平面移动模型,建立了此模型下晶体微观结构与自旋哈密顿参量之间的定量关系.在考虑自旋与自旋、自旋与另一电子轨道和轨道与轨道作用等微小磁相互作用的基础上,采用全组态完全对角化方法,对Al2O3晶体中V3+的局域结构和自旋哈密顿参量进行了系统的研究.结果表明,V3+掺入Al2O3晶体后,上下配体氧平面间距离增大了0.0060 nm.从而成功地解释了Al2O3:V3+晶体的自旋哈密顿参量.在此基础上,研究了三角晶场下3d2离子自旋哈密顿参量的微观起源.研究发现,自旋三重态对自旋哈密顿参量的贡献是主要的,微小磁相互作用对自旋哈密顿参量的贡献只与自旋三重态有关. 相似文献
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D. V. Volkov A. A. Demidov N. P. Kolmakova 《Journal of Experimental and Theoretical Physics》2008,106(4):723-730
The magnetic properties of an easy-axis trigonal DyFe3(BO3)4 antiferromagnetic crystal have been theoretically studied. On this basis, recent experimental data [1] on the field and temperature dependences of magnetization and the temperature dependence of the initial magnetic susceptibility for three crystallographic directions in this antiferromagnet have been interpreted. The characteristics of the trigonal crystal field for the rare earth ion and the parameters of the Fe-Fe and Fe-Dy exchange interactions are determined. Limitations imposed by features of the magnetic characteristics (anisotropic magnetization in the three crystallographic directions, Schottky-type anomalies in the magnetic susceptibility, etc.) on the possible splitting of the ground-state multiplet in the crystal field and the splitting of the lowest doublet due to the f-d interaction for Dy3+ ions are established. 相似文献