Magnetic order in geometrically frustrated Gd2(Ti1−xZr

Da-Qian Liao

¹

,

Martin R. Lees

²

,

Daniel William Baker

³

et al.

Abstract

Single crystals of Gd 2 (Ti 1−x Zr x) 2 O 7 with x = 0.02 and 0.15 have been used to investigate the effects of Zr doping on the properties of the geometrically frustrated antiferromagnet Gd 2 Ti 2 O 7. Powder and single-crystal x-ray data, along with optical birefringence measurements, reveal that the x = 0.02 sample retains the cubic F d3m structure of pure Gd 2 Ti 2 O 7 , while the x = 0.15 composition adopts a tetragonal I 4 1 /amd structure. Low-temperature magnetization and specific heat measurements show that for Gd 2 (Ti 0.98 Zr 0.02) 2 O 7 there are two magnetic transitions at T N1 = 1.02 K and T N2 = 0.70 K, but for Gd 2 (Ti 0.85 Zr 0.15) 2 O 7 a single transition is observed at T N = 1.02 K. Changes in the specific heat with a magnetic field applied along the [110] and the [111] directions are used to construct the H-T phase diagrams for both samples.

Structural Diversity of Ordered Pyrochlores

“…In the tetragonal phase, the A 8c atoms are surrounded by four X 16g atoms, two X 8c atoms, and two Y 4b atoms and located in the center of the hexagonal rings formed by distorted octahedra [B 8d X 16g 4 X 8c 2 ]. The substances having this structure are Sm 2 Ti 2 O 7 and Sm 0.5 Li 0.5 TiO 3 , Tm 2 Mn 2 O 7 , Ca 2 Zr 5 Ti 2 O 16 , CsFe 2 F 6 , Pb 3 Nb 2 O 8 , CsTaWO 6 , and Gd 2 (Ti 1– x Zr x ) 2 O 7 with x = 0.15 . The peculiar example of tetragonal anion-ordered pyrochlore with space-group I 4 1 / amd is lacunar palladium oxychlorid Pd 2 OCl 2 .…”

“…The substances having this structure are Sm 2 Ti 2 O 7 and Sm 0.5 Li 0.5 TiO 3 , 87 Tm 2 Mn 2 O 7 , 88 Ca 2 Zr 5 Ti 2 O 16 , 89 CsFe 2 F 6 , 90 Pb 3 Nb 2 O 8 , 91 CsTaWO 6 , 92 and Gd 2 (Ti 1−x Zr x ) 2 O 7 with x = 0.15. 93 The peculiar example of tetragonal anion-ordered pyrochlore with…”