Bulk magnetization of the heavy rare earth titanate pyrochlores - a series of model frustrated magnets.
J PHYS-CONDENS MAT
483 - 495.
We describe magnetization measurements on the heavy rare earth titanate pyrochlores R2Ti2O7, where R = Gd, Dy, Ho, Er, Yb, in the temperature range: 1.8-300 K, and the field range 0-70 000 Oe. In these materials magnetism arises from the rare earth ions, while Ti is non-magnetic. Analysis of the low held susceptibility versus temperature curves shows that Gd2Ti2O7 has antiferromagnetic coupling (theta approximate to -9 K), which suggests that it is an example of a frustrated antiferromagnet on the pyrochlore lattice. Er2Ti2O7 is likewise found to have a large negative Curie-Weiss temperature, theta approximate to -22 K, which we argue is indicative of antiferromagnetic coupling. Ho2Ti2O7, Dy2Ti2O7 and Yb2Ti2O7 are found to have weak ferromagnetic coupling (theta approximate to 2 K, 1 K and 1 K respectively) which may be largely dipolar in origin. Fitting of the high held magnetization versus field curves suggests a strong [1, 1, 1] single ion anisotropy that identifies these three materials as possible realizations of the ferromagnetic 'spin ice' model.
|Title:||Bulk magnetization of the heavy rare earth titanate pyrochlores - a series of model frustrated magnets|
|Keywords:||CRITICAL-BEHAVIOR, ANTIFERROMAGNET, LATTICE|
|UCL classification:||UCL > School of BEAMS
UCL > School of BEAMS > Faculty of Maths and Physical Sciences
Archive Staff Only