Magnetic susceptibilities and anisotropy studies of holmium pyrogermanate (Ho2Ge2O7) crystal

Structure and magnetic properties of theHo2Ge2O7pyrogermanate

“…Ho 2 Ge 2 O 7 crystallizes as tetragonal, transparent plates and is therefore insulating. Although the anisotropic magnetic dc susceptibility has been previously reported [6], no field-dependent measurements exist to date. In addition, the spin freezing that has been observed in the isotypical systems R 2 Ti 2 O 7 for R = Dy [10][11] or Ho [12][13], in which the Ising character of Ho and Dy and the crystal field are critical to the observed spin relaxations, motivated us to perform a study of the frequency-and field-dependent anisotropic ac susceptibility in Ho 2 Ge 2 O 7 .…”

“…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.…”

Magnetothermodynamics of the Ising antiferromagnetDy2Ge2O7

“…Instead of having a cubic pyrochlore structure with a sublattice of magnetic corner-sharing tetrahedra, rare-earth pyrogermanates are reported to have either triclinic (for Ln = La, Pr, or Nd-Gd), tetragonal (for Ln = Gd-Lu), or monoclinic structures (Sc 2 Ge 2 O 7 ) [11]. DC magnetic susceptibility measurements of Tb, Dy, and Ho-based pyrogermanate single crystals show magnetic anisotropy resulting from strong crystal field effects [12,13,14]. In this paper, we explore the low temperature properties of Dy 2 Ge 2 O 7 , including DC magnetization, AC susceptibility, and heat capacity measurements.…”

“…Rare-earth based pyrogermanates (Ln 2 Ge 2 O 7 ), with a similar chemical formula, but a different structure from the pyrochlores, have also attracted considerable attention [11,12,13,14,15,16,17]. Instead of having a cubic pyrochlore structure with a sublattice of magnetic corner-sharing tetrahedra, rare-earth pyrogermanates are reported to have either triclinic (for Ln = La, Pr, or Nd-Gd), tetragonal (for Ln = Gd-Lu), or monoclinic structures (Sc 2 Ge 2 O 7 ) [11].…”

Measurements of magnetic susceptibilities, their anisotropies and crystal field investigations of monoclinic single crystals of Ho2GeO5

“…Among these rare earth germanates, several rare earth pyro-germanates (R 2 Ge 2 O 7 ) were investigated because of their simple crystal structure and the high site symmetry of the R ion in the crystal matrix [1][2][3]6,7,9,13]. Also, the physical properties viz., optical absorption spectra [4,5], magnetic measurements [10,12,16,18,19], nuclear hyperfine properties [11,17,19] including Mö ssbauer effect measurements [14] were carried out on several rare earth pyrogermanates. But in case of rare earth ortho-germanates (ROGs), no study, except the crystal structure investigations [8], is noticed by the authors.…”