Asymmetry of the splitting of the fluorescence spectrum of Cr3+ in GdAlO3

The fluorescence spectrum of Cr³⁺ in the antiferromagnet GdAlO₃ consists of four broad bands whose peak energies are not perfectly equidistant. A theory recently proposed for the splittung of the fluorescence of a magnetic impurity in a magnetic matrix accounts for the small asymmetry observed.     

Electric field effects in EPR of the SrTiO3 :Cr5+ Jahn-Teller system

It is shown that a static electric field affects the intensity ratio of the EPR lines of Cr⁵⁺ (d₁) in SrTiO₃ at 77K. The experimental results can be accounted for quantitatively by considering for the ${}^2\text{T}{}_{\mathrm{2g}}$ electronic ground state of Cr⁵⁺ a strong Jahn-Teller interaction with localized ρ_g mode. The degeneracy of the resulting vibronic ground state is lifted appreciably by a macroscopic strain which, as a result of the large electrostrictive coupling in SrTiO₃, is induced at moderate electric field strengths.     

Infrared electronic transitions of Eu+3 in GdAlO3

Infrared ⁷F_O → ⁷F_J electronic transitions are reported for Eu⁺³ in GdAlO₃. The low symmetry of the crystalline field allows the observation, for the first time, of transitions with J = 3, 4, 5 and 6. The spectra are explained by means of a crystal-field model where a C_s term is added as a perturbation to the cubic field in order to take into account the lattice distortion. This model predicts energy levels which are in good agreement with the experimental data.     

Resonant cross-relaxation between Cr3+ and V3+ in Al2O3

Cross-relaxation, which occurs when a V³⁺ transition is resonant with a monitored Cr³⁺ transition, leads to a marked reduction of the spin-lattice relaxation time of Cr³⁺ in Al₂O₃. Measurements and an analysis of the temperature dependence of this effect give a value of 8.34 ± 0.49 cm^?1 for the zero-field splitting of V³⁺, an ion which is strongly coupled to the lattice.     

Thermal conductivity of KMgF3 : Cr2+

Observations of resonant scattering of thermal phonons Cr²⁺ ions in KMgF₃ are presented. The results are interpreted with the cluster model of Fletcher and Stevens.     

Magnetic field dependent optical dephasing in LaF3:Er3+

Optical dephasing of the 5388 Å transition between the lowest Kramers doublets of the ⁴S_{$\text{3}\text{2}$} and ⁴I_{$\text{15}\text{2}$} multiplets of Er³⁺:LaF₃ has been studied by photon echo, optical phase switching and optical free induction decay. Er³⁺?¹⁹F hyperfine interactions produce dephasing which is two orders of magnitude faster than in previously studied non-Kramers systems, but at high field changes in the spin dynamics result in microsecond dephasing. For the lower Zeeman component of ⁴S_{$\text{3}\text{2}$}, T₂ (=6μs) is independent of H₀ whereas for the upper component the dephasing is rapid and strongly field dependent. This is quantitatively accounted for by spin lattice relaxation of the upper component of ⁴S_{$\text{3}\text{2}$}. Below 20 kG concentration and temperature dependent dephasing due to electron spin diffusion is observed.     

超声场对钛基PbO2电极电化学氧化Cr3+过程电流效率的影响

本文研究了超声场对Ti／SnO2 Sb2O3／PbO2电极电化学氧化Cr3 过程的影响,探讨了在不同的操作电流密度、反应温度、硫酸浓度及Cr3 浓度下,超声场对硫酸介质中Cr3 电化学氧化生成Cr2O72-过程中的电流效率的影响,并用扫描电镜对有无超声场时不同反应时间下的电极形貌进行了分析。实验结果表明:在相同的反应条件下,有超声场作用时Cr3 电化学氧化过程的电流效率明显高于无超声场时的电流效率。扫描电镜测定发现,有超声场作用时不同反应时间下电极的形貌有明显的变化。     

Magnetic ordering in gadolinium aluminate,GdAlO3

An analysis of Magneto-Electric Susceptibility, Magnetic Susceptibility and X-ray results has shown that the direction of sub lattice alinement in the antiferromagnetically ordered state of GdAlO₃ corresponds to the orthorhombic a-axis. This result is contrary to the previous analysis which favoured the b-axis.     

KMgF3:Cr3+的EPR参量和K+空位研究

EPR和ENDOR表明:顺磁离子取代KMgF₃中的Mg²⁺离子后,所处的环境具有轴对称。本文研究了KMgF₃:Cr³⁺的Δg=g_∥-g_⊥和零场分裂值D,证实KMgF₃:Cr³⁺中K⁺空位的存在。并且指出:由于K⁺空位,使Cr³⁺的最近邻F^-离子分 关键词：     

KZnF3:Cr3+和KMgF3:Cr3+四角对称电子顺磁共振参量与晶格缺陷的研究

用Newman叠加模型研究了KZnF₃:Cr³⁺四角对称基态的零场分裂,证实了Zn²⁺空位和畸变的存在;并指出,空位对晶场的贡献不可忽略。计算得到:KZnF₃:cr³⁺晶体[0,01]方向的一个F^-配体向Cr³⁺移动Δ(KZnF₃)=0.0029-0.0043nm。还研究了KMgF₃:Cr^{3+关键词：}     

Cr3+/Tm3+/Ho3+共掺氟磷酸盐玻璃的制备及性能表征

制备了不同 Al(PO₃)₃含量的掺铥系列氟磷酸盐玻璃,研究了其结构、热稳定性和光谱性质. 研究了不同摩尔百分数 Al(PO₃)₃掺杂下 Cr³⁺/Tm³⁺/Ho³⁺共掺氟磷酸盐玻璃在 2.0μm 处的发光特性. 并且用Judd-Ofelt理论计算了强度参量,并由此计算了激发能级的自发辐射跃迁速率、辐射寿命、荧光分支比等光谱参量. 结果表明,随着 Tm³⁺浓度增加,2.0μm 处发光的强度逐渐增强. 证明了Tm³⁺(³F₄) →Ho³⁺(⁵I₇)能量转移是非常有效的,并与掺杂浓度有关. 关键词： 氟磷酸盐玻璃 能量传递 荧光光谱 吸收光谱     

KZnF3:Cr3+ — A tunable solid state NIR-laser

Pulsed laser operation at room temperature and cw laser output below 260 K has been demonstrated with the laser material KZnF₃:Cr³⁺ in the spectral range between 775—826 nm. The system can be tuned by dispersive elements in the resonator or by temperature variation.     

Spectroscopy of multisites Cr3+ and Nd3+ in yttrium aluminium garnet

Cr³⁺ and Nd³⁺ non-equivalent crystal field sites were observed. By use of a high-resolution dye laser,²E and⁴A₂ splittings, zero-phonon⁴A₂ ²E,²T₁,⁴T₂ transitions and vibronic levels of²E doublets of Cr³⁺ non-equivalent centres were recorded. Energy transfers from Cr³⁺ multisites to Nd³⁺ were studied by site-selective spectroscopy and fluorescence decays.     

The sign of Fe3+OCr3+ superexchange determined from Fe57 hyperfine field measurements

The sign of the super-transferred hyperfine field at an impurity site is shown to depend on the sign of the impurity-host superexchange interaction. This fact is used to determine that the Fe³⁺OCr³⁺ superexchange in YCrO₃ is antiferromagnetic.     

红宝石Cr3+:Al2O3的电子云延伸效应及压力对电子云延伸效应影响(英文)

本文以Cr³⁺自由离子的3d电子径向波函数为基础,对Cr³⁺:Al₂O₃中的电子云延伸效应进行了理论研究,引入了电子云延伸效应系数κ,得到了Cr³⁺:Al₂O₃中Cr³⁺离子的最优化3d电子径向波函数.并研究了压力对电子云延伸效应系数κ的影响.     

Cr3+掺杂的Cd3Al2Ge3O12光谱特性及晶场参数计算

采用高温固相法合成了Cd₃Al₂Ge₃O₁₂：Cr³⁺多晶材料,利用X射线衍射对其结构进行了分析,通过Cr³⁺的室温吸收光谱、室温和77K发射光谱分别对其光谱特性和晶场参数进行了分析和计算.结果表明：在450 nm的蓝光激发下,Cd₃Al₂Ge₃O₁₂：Cr³⁺室温发 关键词： 3Al₂Ge₃O₁₂：Cr³⁺')" href="#">Cd₃Al₂Ge₃O₁₂：Cr³⁺ 荧光光谱 晶场参数 可调谐激光     

Eu^3＋：Sm^3＋：Cr^3＋：YAG红色单晶荧光体

报道外延生长的多激活中心掺杂的红色单晶荧光体Ｅｕ＾３＋：Ｓｍ＾３＋：Ｃｒ＾３＋：ＹＡＧ,其直径达到５４ｍｍ,荧光色坐标为ｘ＝０．６１３７,ｙ＝０．３７３８,相当于波长λ＝５９９ｍｍ的红色荧光,具有较高的色饱和度。这种单晶材料具有委好的抗电子束灼伤能力,在入射能量达到１０＾５Ｗ／ｍ＾２时无发光猝灭现象,是一种较理想的红色单晶荧光材料。     

Cr4+在Al2O3多晶体中的光谱性能研究

采用传统无压烧结工艺制备Cr:Al₂O₃透明多晶陶瓷.测定了其退火前后的吸收光谱和荧光光谱，发现在Al₂O₃六配位的八面体结构中，Cr⁴⁺的荧光发射也处在1100—1600nm波段的红外区间，荧光发射峰位于1223nm附近，类似Cr⁴⁺在四面体中的发光行为.同时由于氧化铝晶格常数较小，晶体场强较强，使Cr⁴⁺:Al₂O_{3< 关键词： 4+')" href="#">Cr⁴⁺ 2}O₃透明陶瓷')" href="#">Cr:Al₂O₃透明陶瓷 光谱性质 八面体     

BeAl2O4:Cr3+的晶场能级

金绿宝石中镜对称格位上Cr³⁺(Ⅱ)离子的⁴T₂,⁴T₁和²E能级与该材料的激光运转有关。⁴T₂和⁴T₁能级各分裂成三个子能级。为从偏振吸收谱上确定BeAl₂O₄:Cr³⁺的能级图,本文计算了⁴T₂和⁴T₁的分裂,找到了对谱方法,得到了表征能级分裂的参量K_{1和K2的值。最后给出了以低点群不可约表示标号的、BeAl2O4:Cr³⁺(Ⅱ)的晶场能级图。 关键词：}     

调谐激光晶体Cr3+:ZnWO4光致发光特性的研究

研究了调谐激光晶体Ｃｒ³⁺：ＺｎＷＯ₄的光致发光特性。报道了它的吸收光谱、激发光谱、发射光谱及其随温度的变化、零声子跃迁和发射寿命等实验结果，并讨论了激发特性、电子－声子耦合作用、ＺｎＷＯ₄中Ｃｒ³⁺的发射寿命曲线等相关问题。 关键词：