The elastic moduli of magnesioferrite spinel, MgFe2 O4, and their temperature dependence have been determined for the first time by ultrasonic measurements on a polycrystalline specimen. The measurements were carried out at 300 MPa and to 700̊C in a gas-medium high-pressure apparatus. On heating, both the elastic bulk (KS) and shear (G) moduli decrease linearly to 350̊C. By combining with extant thermal-expansion data, the values for the room-temperature KS and G, and their temperature derivatives are as follows: K0 = 176.3(7) GPa, G0 = 80.1(2) GPa, (∂KS∂T)P = -0.032(3) GPa K-1 and (∂G/∂T P = -0.012(1) GPa K-1. Between 350 and 400̊C, there are abrupt increases of 1.4% in both of the elastic moduli; these closely coincide with the magnetic Curie transition that was observed by thermal analyses at about 360̊C.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Geochemistry and Petrology