Large magnetic-field-induced strains in sintered chromium tellurides

Sintered samples of Cr3Te4 and Cr2Te3 are found to show large strains accompanied by large volume changes under a magnetic field. In Cr3Te4, volume increases of ΔV/V = 500–1170 ppm by applying a magnetic field of 9 T are observed over the entire temperature range below 350 K. At room temperature, the ΔV/V value exceeds 1000 ppm, which is considerably larger than the maximum values reported for Cr-based magnets, thus far, and is comparable to the room-temperature value of forced-volume magnetostriction in invar alloys. Cr2Te3 shows a large ΔV/V of 680 ppm when applying a magnetic field of 9 T at 200 K. Both samples display particularly large volume increases around the Curie temperature, where they also show negative thermal expansion due to the microstructural effects, suggesting that the cooperation between anisotropic lattice deformation associated with the magnetic ordering and microstructural effects is essential for the manifestation of the large magnetic-field-induced volume changes.