An in situ composite composed of ceria-stabilized tetragonal zirconia polycrystals (Ce-TZP) and La{Co0.5Fe0.5(Fe0.9Al0.1)(11))(11)}- was synthesized from a powder mixture of Ce-TZP, La(Fe0.9Al0.1)O-3, Fe2O3, Al2O3, and CoO. The dense Ce-TZP dispersed with platelike La{Co0.5Fe0.5(Fe0.9Al0.1)(11))O-19 crystals as a second phase were formed after sintering from 1250degrees to 1350degreesC. The saturation magnetization of the in situ composite Ce-TZP/La{Co0.5Fe0.5(Fe0.9Al0.1)11}O-19 was proportional to the mass fraction of the hexaferrite second phase in Ce-TZP. The coercivity of the composite with a 20 mass% of second phase decreased from 9.14 to 2.52 kOe (from 728 to 201 kA/m) after the pulverization of the composite. The susceptibility (chi) increased by 15%-25% under uniaxial stress on the composite. The change of the susceptibility (Deltachi/chi) value increased with decreasing the mass fraction of the second phase in the composite. The Deltachi was found to increase linearly with applied stress and abruptly change on cracking, which is expected for the application in fracture sensing of the composite.