Magnetization measurements and short range order in the system ZnCr2xAl2-2xS4

Structural and magnetic properties of Zn1−xSbxCr2−x/3Se4 (x=0.11, 0.16 and 0.20) single crystals

“…3 and 4. In general, the observed behaviour is very similar to that reported in the literature for the parent compound ZnCr 2 Se 4 [1][2][3][4][5][6][7][8][9][10][11][12][13]. In each case the magnetic susceptibility follows a Curie-Weiss law only above room temperature with the effective magnetic moment of about 3.8 m B (Table 5), which is close to the spin-only value for free Cr 3+ ion with 3d 3 configuration (3.86 m B ), seen also for ZnCr 2 Se 4 [11,12].…”

“…In the paramagnetic region the magnetic behaviour of ZnCr 2 Se 4 is characterized by the effective magnetic moment m eff ¼ 3.87 m B and the paramagnetic Curie temperature y p ¼ 115 K [12,13]. The compound exhibits semiconducting properties with p-type conductivity [6,14].…”

“…Below T N ¼ 20 K the compound reveals complex helimagnetic spin order, which results from competing ferromagnetic (F) and antiferromagnetic (AF) interactions [1][2][3][4][5][6][7][8][9][10][11][12][13]. Sharp specific heat anomaly, negative thermal expansion, and colossal magnetostriction, altogether pointed out to distinct spin-lattice correlations and spin-driven origin of the tetragonal structure distortion observed below T N [8].…”

Structural and magnetic properties of single-crystalline spinel systems ZnCr2−xAlxSe4 (x=0.15 and 0.23)

“…Another possibility is the presence below T N of a spinglass-like state. As discussed for example for the closely related sulphides ZnCr 2x Al 2−2x S 4 [6,24] and CdCr 2x In 2−2x S 4 [24] the magnetic order in the spinel systems result from the competition between ferromagnetic first-nearest neighbours and antiferro- magnetic higher-order neighbours. For some ratio between the strength of these exchange interactions a spin-glass state develops, which manifests itself by magnetic properties similar to that presented in Fig.…”

“…Various types of magnetic order together with concomitant semiconducting behaviour have been reported for chalcogenide spinel materials [2][3][4][5][6][7]. These properties can be modified in a broad range of compound composition, as the spinel crystal structure allows for different cationic substitutions [8][9][10].…”