We present an extended X-ray absorption fine structure study at the Mo K-edge of A2(Mo1−yMny)2O7 (A = Gd, Ho; y = 0.05 and 0.10) pyrochlores, as a function of temperature and composition, coupled to diffractometric and magnetic characterizations. Extending the study reported in our previous paper on the pristine A2Mo2O7 compounds to these Mo/Mn partially substituted samples, where we hypothesize a competition between double-exchange and superexchange couplings, we aim to check which structure parameters are related to the nature of the nearest-neighbor magnetic interactions, looking for the presence and evolution of order and structure anomalies. Two Ho samples Ho2(Mo1−yMny)2O7 (y = 0.05 and 0.10) keep the spin-glass nature of the parent compositions with a strong distortion of the MoO(1)6 octahedron and of the Mo‒Ho and Mo‒Mo second shell. On the other hand, two Gd2(Mo1−yMny)2O7 samples, ferromagnetic at low temperature in the undoped case, show the appearance on a local scale of a spin-glass transition mirrored by a quite high structure disorder and by a distortion coherent with a lattice frustration after Mn-doping. Therefore, the Gd and Ho Mn-doped samples display a similar frustrated behavior, differently from the corresponding undoped ones.

Local disorder and structure relation induced by magnetic exchange interactions in A2(Mo1−yMny)2O7 pyrochlores / C. Castellano, M. Scavini, G. Berti, F. Rubio-Marcos, G. Lamura, S. Sanna, E. Salas-Colera, A.-. Munoz-Noval, M.R. Cimberle, F. Demartin. - In: JOURNAL OF ALLOYS AND COMPOUNDS. - ISSN 0925-8388. - 865(2021 Jun 05), pp. 158958.1-158958.14. [10.1016/j.jallcom.2021.158958]

Local disorder and structure relation induced by magnetic exchange interactions in A2(Mo1−yMny)2O7 pyrochlores

C. Castellano
Primo
;
M. Scavini
Secondo
;
F. Demartin
Ultimo
2021

Abstract

We present an extended X-ray absorption fine structure study at the Mo K-edge of A2(Mo1−yMny)2O7 (A = Gd, Ho; y = 0.05 and 0.10) pyrochlores, as a function of temperature and composition, coupled to diffractometric and magnetic characterizations. Extending the study reported in our previous paper on the pristine A2Mo2O7 compounds to these Mo/Mn partially substituted samples, where we hypothesize a competition between double-exchange and superexchange couplings, we aim to check which structure parameters are related to the nature of the nearest-neighbor magnetic interactions, looking for the presence and evolution of order and structure anomalies. Two Ho samples Ho2(Mo1−yMny)2O7 (y = 0.05 and 0.10) keep the spin-glass nature of the parent compositions with a strong distortion of the MoO(1)6 octahedron and of the Mo‒Ho and Mo‒Mo second shell. On the other hand, two Gd2(Mo1−yMny)2O7 samples, ferromagnetic at low temperature in the undoped case, show the appearance on a local scale of a spin-glass transition mirrored by a quite high structure disorder and by a distortion coherent with a lattice frustration after Mn-doping. Therefore, the Gd and Ho Mn-doped samples display a similar frustrated behavior, differently from the corresponding undoped ones.
A. Oxide materials; C. Exchange and superexchange; C. Order-disorder effects; D. EXAFS; D. X-ray diffraction
Settore CHIM/03 - Chimica Generale e Inorganica
Settore FIS/03 - Fisica della Materia
1-feb-2021
Article (author)
File in questo prodotto:
File Dimensione Formato  
JALCOM_865_158958_2021.pdf

accesso riservato

Descrizione: Articolo principale
Tipologia: Publisher's version/PDF
Dimensione 1.25 MB
Formato Adobe PDF
1.25 MB Adobe PDF   Visualizza/Apri   Richiedi una copia
manuscript_Castellano_revised.pdf

embargo fino al 05/06/2023

Tipologia: Post-print, accepted manuscript ecc. (versione accettata dall'editore)
Dimensione 2.66 MB
Formato Adobe PDF
2.66 MB Adobe PDF   Visualizza/Apri   Richiedi una copia
Pubblicazioni consigliate

Caricamento pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/827682
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 0
  • ???jsp.display-item.citation.isi??? 0
social impact