DocumentCode :
1322803
Title :
Structure, Magnetism and Magnetoresistance Effect of 
(  ceramics have been prepared by a solid state reaction method. The X-ray diffraction patterns suggest that the samples have a cubic spinel phase with a space group <i>Fd</i>3<i>m</i> and a tiny amount of Cr<sub>2</sub>O<sub>3</sub> impurity phase. X-ray photoemission spectroscopy reveals a bivalence of Cu and trivalence of Cr in Cd<sub>0.8</sub>Cu<sub>0.2</sub>Cr<sub>2</sub>S<sub>4</sub>. The replacement of Cd by Cu leads to a slight shift of magnetic transition temperature <i>T</i><sub>C</sub>. The saturation magnetic moment per formula unit at 2 K and effective moments in paramagnetic region decrease with Cu content, which is attributed to the coexistence of low spin state Cr<sup>3+</sup> with <i>S</i>=1/2 and high spin state Cr<sup>3+</sup> with <i>S</i>=3/2 as deduced from the <i>M</i>-<i>H</i> and <i>M</i>-<i>T</i> measurements. The transport measurements suggest that the Cu<sup>2+</sup> doping enhances the carrier density. In contrast, a significant decrease in magnetoresistance is observed upon Cu doping. The magnetoresistance effect is discussed based on the magnetic polaron theory.</div>
</div>
<div class='row'>
<div class='leftDiv labelDiv col-xs-4 col-sm-2 fullRecLabelEnglish'>Keywords : </div><div class='valueDiv leftDirection leftAlign col-xs-8 col-sm-10 fullRecValueEnglish'>Curie temperature; X-ray diffraction; X-ray photoelectron spectra; cadmium compounds; carrier density; ceramics; copper compounds; crystal structure; impurity states; magnetic moments; magnetic polarons; magnetoresistance; paramagnetic materials; space groups; Cd<sub>1-x</sub>Cu<sub>x</sub>Cr<sub>2</sub>S<sub>4</sub>; Cr trivalence; Cu bivalence; Cu content; Cu<sup>2+</sup> doping; M-H measurements; M-T measurements; X-ray diffraction; X-ray photoemission spectroscopy; carrier density; ceramics; cubic spinel phase; impurity phase; magnetic polaron; magnetic transition temperature; magnetism; magnetoresistance effect; paramagnetic region; saturation magnetic moment; solid state reaction; space group; spin state; structural properties; temperature 2 K; transport measurements; Conductivity; Copper; Ions; Magnetic properties; Magnetization; Saturation magnetization; Temperature measurement; <formula formulatype=)
${rm Cd}_{1-{rm x}}{rm Cu}_{rm x}{rm Cr}_{2}{rm S}_{4}$ ; magnetism; solid-state reaction;
fLanguage :
English
Journal_Title :
Magnetics, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9464
Type :
jour
DOI :
10.1109/TMAG.2012.2199286
Filename :
6333013
Link To Document :
