MAGNETIC-ORDERING IN DISORDERED SPINELS ZNXMG1-XFECRO4

The magnetic properties of the disordered spinel system ZnxMg1-x-FeCrO4 (x = 0.0, 0.2, 0.4, 0.6, 0.8) have been investigated through Mossbauer spectroscopy, magnetization and susceptibility measurements. Magnetization results indicate a canting of the B-site moments with an average canting angle that increases with x suggesting the magnetic structure to be non-collinear. Mossbauer results show the presence of two types of spin-spin relaxation: smaller magnetic clusters relaxing at a faster rate which give rise to a quadrupole doublet at x less-than-or-equal-to 0.4 at 300 K, while for x greater-than-or-equal-to 0.6, the observed behaviour at 80 K and 300 K suggests a cluster spin glass type of ordering. The results of the a.c. susceptibility show normal ferrimagnetic behaviour for x less-than-or-equal-to 0.4 and for x greater-than-or-equal-to 0.6, they show the existence of magnetic ordering, which supports the Mossbauer measurements.