Short-range antiferromagnetic interaction and spin-phonon coupling in La2CoMnO6 double perovskite

Weak antiferromagnetic (AFM) interaction in the ferromagnetic (FM) partially ordered La2CoMnO6 (LCMO) was detected by Raman spectroscopy by monitoring spin-phonon coupling. Because of the sensibility to probe short-range disorder and lattice modifications, the Raman spectroscopy showed to be an useful tool to indicate less remarkable magnetic transitions in LCMO compound. Apart from the expected spin-phonon coupling due to the long-range FM superexchange (T-c similar to 230 K), phonons parameters pointed out an additional spin-phonon coupling related to the short-range AFM interaction at Tc similar to 135 K, which was not detected from the magnetic bulk response. These results reinforce the Raman spectroscopy as a powerful technique to detect antisite disorder into A(2)B'B''O-6 magnetic double perovskites, whose magnetic properties are driven by superexchange interactions.