| Texto completo | |
| Autor(es): |
Medrano, C. P. C.
;
Sadrollahi, E.
;
Da Fonseca, R. G. M.
;
Passamani, E. C.
;
Freitas, D. C.
;
Continentino, M. A.
;
Sanchez, D. R.
;
Litterst, F. J.
;
Baggio-Saitovitch, E.
Número total de Autores: 9
|
| Tipo de documento: | Artigo Científico |
| Fonte: | PHYSICAL REVIEW B; v. 103, n. 6, p. 10-pg., 2021-02-24. |
| Resumo | |
The magnetic properties of site-disordered Ni5Sn(O2BO3)(2) ludwigite have carefully been studied using local probes and bulk experimental methods in temperatures down to 1.6 K and magnetic fields up to 9 T. Our results have clearly shown the role of the effect of order/disorder site occupancy in these complex compounds with spin moments S = 1. Different from most ludwigites, site-disordered Ni5Sn(O2BO3)(2) ludwigite has shown three magnetic transitions at 80, 50, and 5 K. Local probes (Sn-119 Mossbauer and muon spin spectroscopy) have indicated a partial long-range magnetic order with onsets at 80 and 50 K with predominant ferromagnetic interactions at 80 K and antiferromagnetic ones at 50 K. At lower temperatures, a partial spin-glass-like freezing of the moments has been developed concomitantly with fraction of the moments ordered at higher temperatures, a spin-glass-like and long-range magnetic order coexist and a spontaneous exchange bias effect has been observed. Applied magnetic fields have gradually reduced magnetic frustration, leading to a magnetically ordered state of the complete structure at 51 K under 9 T. The absence of double-exchange interactions in order/disorder Ni5Sn(O2BO3)(2) ludwigites shows how the magnetic interactions that compete as direct exchange and double exchange are modified by the site occupancy of nonmagnetic Sn ions. Features as a third magnetic transition, the appearance of spontaneous exchange bias, and the enhancement of the coercive field at low temperatures were not found in the site-ordered isomer compound. (AU) | |
| Processo FAPESP: | 09/54082-2 - EMU: projeto para aquisição de um magnetômetro de amostra vibrante que utiliza como sensor um dispositivo supercondutor de interferência quântica acoplado (Squid-VSM) com circuito fechado de criogenia |
| Beneficiário: | Ernesto Chaves Pereira de Souza |
| Modalidade de apoio: | Auxílio à Pesquisa - Programa Equipamentos Multiusuários |