Magnetic dimers and trimers in the disordered S=3/2 spin system BaTi1/2Mn1/2O3

Autor(es)

Garcia, F. A. ; Kaneko, U. F. ; Granado, E. ; Sichelschmidt, J. ; Hoelzel, M. ; Duque, J. G. S. ; Nunes, C. A. J. ; Amaral, R. P. ; Marques-Ferreira, P. ; Lora-Serrano, R.

• Tipo de documento: Artigo Científico
• Fonte: PHYSICAL REVIEW B; v. 91, n. 22, p. 8-pg., 2015-06-11.

Resumo

We report a structural-magnetic investigation by x-ray absorption spectroscopy (XAS), neutron diffraction, dc susceptibility (X-dc), and electron spin resonance (ESR) of the 12R-type perovskite BaTi1/2Mn1/2O3. Our structural analysis by neutron diffraction supports the existence of structural trimers with chemically disordered occupancy of Mn4+ and Ti4+ ions, with the valence of the Mn ions confirmed by the XAS measurements. The magnetic properties are explored by combining dc-susceptibility and X-band (9.4 GHz) electron spin resonance, both in the temperature interval of 2 <= T <= 1000 K. A scenario is presented under which the magnetism is explained by considering magnetic dimers and trimers, with exchange constants J(a)/k(B) = 200 (2) K and J(b)/k(B) = 130 (10) K, and orphan spins. Thus, BaTi1/2Mn1/2O3 is proposed as a rare case of an intrinsically disordered S = 3/2 spin gap system with a frustrated ground state. (AU)

• Processo FAPESP: 11/22261-5 - Efeito da não estequiometria em filmes finos de ligas de Heusler nas características do tunelamento spin-dependente de junções tunel X2YZ/MgO: XAS e XMCD
• Beneficiário: Fernando Assis Garcia
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado