Temperature anomalies of the hyperfine magnetic fields on 111Cd probe nuclei in ferro- and antiferromagnetic phases of the ordered FeRh alloys
Carregando...
Data
Data de publicação:
2016
Orientador
Título da Revista
ISSN da Revista
Título do Volume
É parte de
É parte de
É parte de
É parte de
INTERNATIONAL CONFERENCE ON HYPERFINE INTERACTIONS AND THEIR APPLICATIONS
Exportar
Resumo
FeRh ordered alloy crystallizes in the bcc B2 structure [1], presents first order phase
transition from antiferromagnetic (AF) ordering at low temperature to ferromagnetic (F)
state above 350 K [2], and shows significant magnetocaloric effect near RT [3]. Recently,
FeRh alloy has also been considered as an interesting material for spintronics applications
[4].
In the AF state, FeRh has compensated AFII-type magnetic structure with μFe=3.3 μB and
μRh=0. In the F state of FeRh both Fe and Rh atoms have magnetic moments of μFe=3.2 μB
and μRh=0.9 μB, respectively [5]. The Fe – Rh compounds were studied by Mössbauer
spectroscopy (MS) on 57Fe [6, 7] and 119Sn probe nuclei [8].
In this work, we have, for the first time, investigated the HFs for 111Cd probe atoms in two
FeRh samples of different composition by perturbed γ-γ angular correlation (PAC)
spectroscopy in the range from 40 K to a temperature above the TC. The alloy Fe0.48Rh0.52 (A1
sample) is AF at low temperatures. At the temperature Tt = 345 K the first order phase
transition is observed, and this compound becomes F at the temperatures lower than TC =
685 K. The alloy Fe0.52Rh0.48 (A2 sample) is only ferromagnetic below TC = 800 K. It was
established that in both alloys 111Cd probes substitute only Fe ions.
The HFs values extrapolated to 0 K were found to be B1(0) =8.70(5) T and B2(0) =5.53(5) T
for AF and F ordering of A1 and A2 samples, respectively. The HF in the AF state is almost
60% higher than the HF in the F alloy. The dependences B1 (T) and B2 (T) show anomalous
behavior. At Tt = 345 K, phase transition AF-F is accompanied by a sharp decrease in the HF
at 111Cd probe nuclei. Earlier, an increase of the corresponding HFs was observed for 57Fe
atoms and 119Sn impurity atoms in the region of AF-F transition by MS in [6] and [8].
Analysis of B1(T) and B2(T) has allowed to obtain the temperature dependences of the
competing contributions BFe (T) and BRh (T) to the HFs on 111Cd probe nuclei in FeRh alloys.
Como referenciar
KRYLOV, V.I.; BOSCH-SANTOS, B.; CABRERA-PASCA, G.A.; CARBONARI, A.W.; SAXENA, R.N.; MESTNIK-FILHO, J. Temperature anomalies of the hyperfine magnetic fields on 111Cd probe nuclei in ferro- and antiferromagnetic phases of the ordered FeRh alloys. In: TEMST, KRISTIAAN (ed.); VANTOMME, ANDRE (ed.); COTTENIER, STEFAAN (ed.); PEREIRA, LINO (ed.). In: INTERNATIONAL CONFERENCE ON HYPERFINE INTERACTIONS AND THEIR APPLICATIONS, July 3-8, 2016, Leuven, Belgium. Abstract... Leuven, Belgium: Instituut voor Kern- en Stralingsfysica, 2016. Disponível em: http://repositorio.ipen.br/handle/123456789/28010. Acesso em: 25 Apr 2024.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.