Structural and magnetic properties of CuCr2Se4-xXx (X = Cl, Br) single crystals

INOR 424

Janell R. Neulinger1, Marco Liberati2, Rajesh V. Chopdekar3, Elke Arenholz4, Andreas Scholl, a_scholl@lbl.gov4, Yuri Suzuki5, Yves Idzerda2, and Angelica M. Stacy1. (1) Department of Chemistry, UC Berkeley, Berkeley, CA 94720, (2) Department of Physics, Montana State University, Bozeman, MT 59717, (3) School of Applied Physics, Cornell University, Ithaca, NY 14853, (4) Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, (5) Materials Science and Engineering, UC Berkeley, 210 Hearst Memorial Mining Building, UC Berkeley, Berkeley, CA 94720
CuCr2Se4 is a highly spin-polarized spinel ferromagnet of interest for magnetic tunnel junctions and other spintronic applications. The conductivity and magnetic properties can be chemically tuned by substitution of halogens onto the selenium anion site. Chemical vapor transport with a variety of transport agents (e.g., SeX4 with X = Cl, Br) yields lightly doped single crystals of CuCr2Se4-x Xx. Crystal habit and single crystal X-ray diffraction reveal symmetry-broken rhombohedral doped phases in contrast to the undoped cubic spinel CuCr2Se4. Bulk magnetic measurements indicate ferrimagnetic behavior to well above room temperature; Curie temperatures are suppressed with increasing doping level. Soft X-ray absorption spectroscopy and X-ray magnetic circular dichroism measurements at the Cu and Cr L2,3 edges confirm the ferrimagnetic model. Magnetic microstructures (domains) observed with the Photoemission Electron Microscope (PEEM) further support the weak uniaxial anisotropy of the rhombohedral doped phases.
 

Solid State and Solid State Materials
8:30 AM-11:50 AM, Monday, 11 September 2006 Moscone Center -- Room 307, Oral

Division of Inorganic Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006