Magnetic structure of the NiCr2O4 nickel chromite

The magnetic properties of the NiCr₂O₄ chromite are investigated and compared with similar properties of the NiFe_1.1Cr_0.9O₄ nickel ferrite-chromite material. It is found for the first time that the tetrahedral (A) sublattice of the NiCr₂O₄ chromite is responsible for the total magnetic moment. Moreover, it is revealed that the NiCr₂O₄ chromite exhibits a giant magnetostriction of the paraprocess (λ _para ～ 200×10^?6) and an anomalously large volume magnetostriction (ω ～ 500×10^?6) at a temperature of 4.2 K in magnetic fields up to ～50 kOe. The inference is made that the observed paraprocess is caused by an increase in the degree of noncollinearity of the magnetic moments induced in the octahedral (B) sublattice of the NiCr₂O₄ chromite in an external magnetic field.