Magneto-optical properties of neodymium-doped LiYF4

Abstract

In this paper we demonstrate the validity of a semi-empirical approach to describe the magneto-optical properties of lanthanide 31 complexes. The polarised absorption (IR-VIS-UV), magnetic circular dichroism (MCD) and magnetic susceptibilities of a LiYF :Nd 4 (1.5%) single crystal were recorded and analysed in a temperature region of 4.2 K up to room temperature. The crystal structure is obtained by means of X-ray analysis. Starting values of the free ion, crystal field and intensity parameter sets were obtained by using an -additive crystal-field model based on the coordinates of the eight F ions in the first coordination sphere (S symmetry). After several 4 iterations the parameter values are optimised and checked by simulations of the optical and magneto-optical spectra and by the simulation of the magnetic susceptibilities.

A few mistakes in widely used data files for configurations calculations

“…De Leebeeck, Binnemans and Go¨rller-Walrand [9] give in their Table 5 all N ¼ 182 calculated energies of the f 3 configuration. We obtain s 1 ¼ 3.8, s 2 ¼ 3.6 and s 3 ¼ 3.6 cm À1 when using the Hamiltonian parameters as they are listed in Table 4 of Ref.…”

Theoretical Studies of the EPR Parameters of Nd3+ in LiYF4

“…In the scheelite-structured crystal LiYF 4 , the impurity Nd 3+ replaces the host Y 3+ and forms a 0932-0784 / 04 / 0400-0235 $ 06.00 c 2004 Verlag der Zeitschrift für Naturforschung, Tübingen · http://znaturforsch.com tetragonally distorted [NdF 8 ] 5− cluster [5,6]. For an Nd 3+ (4f 3 ) ion under tetragonal symmetry, its ground 4 I 9/2 configuration may be split into five Kramers doublets because of the spin-orbit coupling and tetragonal crystal-field interactions.…”

“…In LiYF 4 , the Y 3+ ion is coordinated to eight nearest F − ions which form the edges of a slightly distorted dodecahedron with S 4 local symmetry [5]. Because of the rather small distortion from D 2d to S 4 [11 -14], the imaginary parts of the rank-4 and rank-6 crystal-field parameters are very small, as pointed out in [13,15], and so their contributions to the coefficient C( 4 I 9/2 ;Γ γ (γ ) M J1 ) or C( 4 I 9/2 ;Γ γ (γ ) M J1 ) in the basis Γ γ (γ ) , and hence to the EPR parameters may be regarded as insignificant.…”

“…t k andĀ k (R 0 ) are, respectively, the powerlaw exponents and the intrinsic parameters (with the reference distance or impurity-ligand distance R 0 ). Among the eight nearest F − ions of the Y 3+ site, four of them are at the distance R 1 H (≈ 2.2481Å) and the angle θ 1 (≈ 67.14 • ), and the other four are at the distance R 2 H (≈ 2.2996Å) and the angle θ 2 (≈ 37.86 • ), where θ i is the angle between R i H and the four-fold axis [5]. Since the ionic radius r i (≈ 0.995Å [18]) of the impurity Nd 3+ is larger than the radius r h (≈ 0.893Å [18]) of the host Y 3+ ion, we can reasonably estimate the impurity-ligand distances R j of the impurity center from the host values R j H and the empirical relationship [19] …”

“…LiYF 4 : Nd 3+ crystal has attracted interest due to its application as laser host [1 -4] and its magneto-optical properties [5]. These properties are closely related to the electronic states and the local structure of the impurity Nd 3+ .…”