resumo
In this work an electric-field gradient and magnetic hyperfine field study of the multiferroic AgCrO2 triangular spin lattice is presented. Perturbed angular correlation measurements at different temperatures, revealed the coexistence of two electric-field gradients, i.e., two distinct local environments at temperatures below 100 K. The emerging second local environment appears as a distortion of the Cr surrounding resulting in a local symmetry lowering. This local distortion emerges much above T-N and concomitantly with the onset of short-range magnetic correlations. We claim that, through a magnetoelastic instability, distinct Cr-Cr exchange interaction pathways appear providing a channel for magnetic frustration release.
palavras-chave
DELAFOSSITE OXIDES ABO(2); RELAXATION; ORDERS; PAC; FE; AG; CU; CR; ND
categoria
Physics
autores
Lopes, AML; Oliveira, GNP; Mendonca, TM; Moreira, JA; Almeida, A; Araujo, JP; Amaral, VS; Correia, JG
nossos autores
Vitor Brás Sequeira Amaral
Professor CatedráticoProjectos
Research on Magnetic and Multiferroic Materials using Radioactive Isotopes at ISOLDE-CERN (CERN/FP/109357/2009)
Perturbed Angular Correlations and Electron Channeling Experiments at ISOLDE - applied materials research with nuclear techniques, training and development (CERN/FP/116320/2010)
MULTIFOX: Nanometric Probing and Modification of Multiferroic Oxides (PTDC/FIS/105416/2008)
agradecimentos
This work was supported by Portuguese Foundation for Science and Technology (Projects No. CERN/FP/109357/2009, No. CERN/FP/116320/2010, and No. PTDC/FIS/105416/2008), European Union with FP7 through ENSAR (Contract No. 262010), German BMBF (Contract No. 05KK7TS2), and ISOLDE Collaboration (Project No. IS487).