Magnetic frustration in zinc chromate spinel

CHED 1189

Sergio Pulido1, Benny C. Chan, chan@tcnj.edu1, Robert J. Cava2, and Arthur P. Ramirez3. (1) Department of Chemistry, The College of New Jersey, 2000 Pennington Rd, Ewing, NJ 08628, (2) Department of Chemistry, Princeton University, Princeton, NJ 08544, (3) Device Physics Research Department, Bell Labs, Alcatel-Lucent, 600 Mountain Ave., Murray Hill, NJ 07974
The effect of non-magnetic ion substitution on the frustrated zinc chromate spinel was studied this past summer. The antiferromagnetic chromium sits in a tetrahedral arrangement creating a geometrically frustrated lattice. In the literature, gallium doping levels greater than 10% would relieve the frustration of the system. We examined gallium dopant levels from 1-5% and discovered a spin glass transition that has not been previously reported. The solid state synthesis of these compounds was optimized. The magnetic properties were examined by a PPMS magnetometer. Powder X-ray diffraction patterns were obtained and analyzed by Reitveld analysis to examine how the dopant level changes the unit cell. Our work demonstrates the ability to alter magnetic properties with very small dopant levels in this spinel system.