Study of optical absorption spectra and magnetic susceptibilities of Tm3+-pyrogermanate (Tm2Ge2O7)

A study on crystal field effect and single ion anisotropy in pyrochlore europium titanate (Eu2Ti2O7)

“…Table 1 Energy eigenvalues (cm −1 ) and eigenfunctions of 7 F 0 , 7 F 1 , 7 F 2 , 5 D 0 , 5 Level Energy Eigenfunctions When fitting experimental results, the starting Free Ion (FI) parameters are taken as that of Eu 3+ -diglycollate (EuDG) [34] which are then varied to fit, as closely as possible, the CG of the 7 F 1-5 terms observed in the absorption and emission spectra of EuT [19]. The FI states thus generated are used to obtain the reduced matrix elements [25]. Finally, CF parameters are varied in order to match the magnetic and Mössbauer results as well as the optical levels as best as possible.…”

“…The reduced matrix elements of U kq are calculated using the IC wave functions by standard procedures [25].…”

Structure and magnetic properties of theHo2Ge2O7pyrogermanate

“…The crystals were well-formed, transparent tetragonal plates with typical dimension 3x3x0.5 mm 3 . We employed powder X-ray diffraction measurements in order to confirm the crystal structure and the purity of the crystals.…”

“…The coordination polyhedron of the rare earth is a distorted pentagonal bipyramid [1][2] with its axis almost parallel to the crystallographic c direction. The optical properties [3][4] and magnetic susceptibility of the R 2 Ge 2 O 7 compounds [3,[5][6][7][8] have often been interpreted in light of the four equivalent magnetic sites per unit cell and their local 5-fold symmetry, though the findings of a Mossbauer study on Er 2 Ge 2 O 7 [9] indicate that the pentagonal crystal field model around the R atoms is invalid at least in that case.…”

Mixed electronic and oxide ionic conduction and migration mechanisms in digermanate La2−xCaxGe2O7−x/2

“…Rare earth digermanates with the general formula of RE 2 Ge 2 O 7 , where RE is the rare earth element (RE = La-Lu), have attracted considerable attention due to their unique structural features which give rise to an interesting and diverse group of low-temperature magnetic states in optical and magnetic activities, ranging from "spin liquid" to "spin glass" through "spin ice" behaviours, all due to the so-called "geometrically frustrated lattice". [30][31][32] The rare earth digermanates RE 2 Ge 2 O 7 exhibit five different structural types, which are five modulated structures based on the special sequences of closed stacking of the heavy atomic layers of RE and Ge. 33,34 The unit cell of cerium germanate is regarded as the basic module (n = 1), in which, with the different stacking consequences of RE and Ge in the heavy atomic layer along the c-axis, RE = La and Er compositions adopt the n = 2 structural type, while Er 2 Ge 2 O 7 exhibits tetragonal symmetry.…”