The magnetic compensation and magnetostriction properties in Fe-doped CoCr 2 O 4 samples have been investigated. Structural and magnetic measurements imply that the doped Fe 3þ ions initially occupy the B1 (Cr) sites when x < 0.1, and then mainly take the A (Co) sites. This behaviour results in a role conversion of magnetic contributors and a composition compensation between two competitively magnetic sublattices at x ¼ 0.1. Temperature-dependent compensation has also been found in the samples with x ¼ 0.1-0.22, with the compensation temperature in the range of 40 -104 K. The Fe 3þ doping also modulates the exchange interaction of the system and prevents the formation of long-range conical order of spins. The magnetoelectric transition temperature at 23 K in CoCr 2 O 4 is shifted to lower temperature by increasing the dopants. The magnetostriction effect in this system has been observed for the first time. The strain has a maximum value of about 280 ppm at x ¼ 0.4. The magnetostriction is consistent with the behaviour of the two magnetic compensations.

No abstract