Size dependence of magnetic and dielectric properties in YCr0.5Fe0.5O3 ceramics

The YCr0.5Fe0.5O3 ceramics with different sintering temperatures (T-s) have been synthesized by a sol-gel method, and the structural, magnetic and dielectric properties are studied. With the decrease of T-s, continuous decrease of grain size is evidenced via the micromorphology analysis. Due to the competition between the single ion magnetic anisotropy and the antisymmetric Dzyaloshinsky-Moriya interaction, the total magnetization becomes zero at the compensation temperature (T-comp) in the presence of a lower magnetic field, and the T-comp exhibits size dependent behavior. With the decrease of grain size, the T-comp becomes lower due to the increase of uncompensated spins. Meanwhile, the T-comp is adjustable by the magnetic field, and a larger external field drives the Tcomp to lower temperature. After cooling the samples in magnetic field, the magnetic anisotropy is established, which results in a positive exchange bias (EB) effect below the T-comp. The decrease of T-s would increase the ferromagnetic component, which leads to the decrease of EB field (H-EB). The dielectric measurements suggest that the samples of T-s = 900 and 800 degrees C possess large permittivity accompanied with dielectric relaxation near room temperature, and the dielectric relaxation which arises from the single-ionized oxygen vacancies moves to higher temperature with the decrease of T-s.

Automated summary

The YCr0.5Fe0.5O3 ceramics with different sintering temperatures exhibit changes in structural, magnetic, and dielectric properties as the grain size decreases with lower sintering temperatures. The competition between single ion magnetic anisotropy and antisymmetric Dzyaloshinsky-Moriya interaction leads to size-dependent total magnetization behavior at the compensation temperature. Adjusting the magnetic field affects the compensation temperature, resulting in a positive exchange bias effect.