Abstract
Two series of B-site ordered, double-perovskite A2CoMnO6 and A2NiMnO6 (A = La, Pr, Nd, Sm, Gd) epitaxial films with thickness d ~ 100 nm were grown on SrTiO3(111) substrates via metalorganic aerosol deposition. Polarization and temperature-dependent Raman spectroscopy were carried out in order to determine the spin-phonon coupling constant, λ, and the impact of the A-site cation radius on the phonon properties. The reduction of the A-site cation radius from La3+ down to Gd3+ systematically shifts the Raman modes to lower wavenumbers, and decreases the magnetization-induced softening of the Ag breathing mode, described by the spin-phonon coupling constant, λ, which changes from λ = 1.42 cm−1 (La2CoMnO6) and λ = 1.53 cm−1 (La2NiMnO6) down to λ = 0.58 cm−1 (Gd2CoMnO6) and λ = 0.44 cm−1 (Gd2NiMnO6). A similar effect of the A-cation radius was established for the c-lattice parameter and Curie temperature, TC, in this series of double-perovskite films. Our observations directly demonstrate a strong impact of the lattice structure on the ferromagnetic superexchange interaction in double perovskites. Moreover, the A2CoMnO6 and A2NiMnO6 series exhibit very similar behavior of spin-phonon coupling due to the only moderate difference of Co2+ and Ni2+ cation size.
Highlights
IntroductionP121 /n1 structure, are promising materials for spintronic applications due to the presence of ferromagnetic ordering, magnetodielectric coupling, and multiferroic behavior [1,2,3,4,5,6,7]
We report the impact of the A-site cation size on the structural, magnetic, and phonon properties of A2 CoMnO6 and A2 NiMnO6 (A = La, Pr, Nd, Sm, Gd) epitaxial films grown on (111)-oriented SrTiO3 (STO) substrates via a metalorganic aerosol deposition (MAD) technique [23]
We observed the systematic reduction of the spin-phonon coupling by decreasing the A-site cation radius, and discussed it in the framework of variation of the internal chemical pressure induced by A-site cations
Summary
P121 /n1 structure, are promising materials for spintronic applications due to the presence of ferromagnetic ordering, magnetodielectric coupling, and multiferroic behavior [1,2,3,4,5,6,7]. They represent an attractive model system, in which the fundamental coupling between spin, charge, and lattice degrees of freedom—and, their electromagnetic properties—strongly depend on the A-site cation radius [5,6,7], on the oxidation state of. We observed the systematic reduction of the spin-phonon coupling by decreasing the A-site cation radius, and discussed it in the framework of variation of the internal chemical pressure induced by A-site cations
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
