An Overview of the Director State in Gadolinium Gallate Garnet

Abstract

In recent years the topic of frustrated magnetism has attracted significant scientific interest that shows little sign of abating. Within the field of frustrated magnetism, the compound Gd3Ga5O12 was, for many years, the archetypal frustrated magnet with a ground state that could not be elucidated. Recently an unusual emergent ground state, a director state, has been determined for Gd3Ga5O12, which is now also observed for other isostructural compounds. In this review an overview of the director state is given, starting with the basics of rare earth magnetism and leading to a summary of the experimental signatures that led to the insight needed to determine the director state.

Frustrated Magnet Mn3Al2Ge3O12 Garnet: Crystal Growth by the Optical Floating Zone Method

“…The magnetic Mn ions are positioned on the A site, forming two interpenetrating hyperkagomé lattices in which the magnetic ions are arranged in corner sharing triangles. These adjacent triangles lie with an angle of 73.2 • between them, creating a three dimensional structure [4]. The antiferromagnetically coupled ions on the triangular lattice facilitate geometric magnetic frustration, prompting interest in the garnet structure.…”

“…The gadolinium gallium garnet (GGG), Gd 3 Ga 5 O 12 , has been extensively studied as the archetypal frustrated magnet [4,[15][16][17]. GGG displays no long-range magnetic order in zero-field despite its relatively strong antiferromagnetic correlations.…”

“…This new director state is derived from the three dimensional triangular arrangement of localised spins and the corresponding perturbative magnetic anisotropy, with the directors localised to the centre of 10-spin loops of the Gd ions [16]. Recent results on gadolinium auminium garnet (GAG) have also piqued interest as a candidate for the 10-spin loop director state [4]. Despite the high theoretical interest in GGG and GAG, the prohibitively high neutron absorption cross section of the Gd isotopes makes it extremely hard to experimentally probe the magnetic structure of Gd compounds using neutron scattering techniques.…”

Oxide Ion Conduction in Ca-Doped Yb3Ga5O12 Garnet

“…Herein, Yb 3 Ga 5 O 12 , which is predicted to have excellent phase stability by Song et al, was therefore selected to identify the possible oxide ion conduction. While gallium-based garnet materials have been extensively studied for their magnetic − and photoluminescence properties , and applications in solid-state lasers, there is a scarcity of research on their electrical properties. In the present work, for the first time, we reported that Ca doping to create oxygen vacancies could successfully introduce oxide ion conduction and significantly improve the electrical conductivity of Yb 3 Ga 5 O 12 by more than two orders of magnitude.…”