Cationic distribution, exchange interactions, and relaxation dynamics in Zn-diluted MnCo2O4 nanostructures

We report an experimental investigation of the electronic structure and magnetic properties of bulk and nanosized MnCo2O4 diluted with Zn. The cationic distribution for tetrahedral A-site dilution is (Co2+1−yAZn2+yA)A[Mn3+Co3+]BO4±δ, whereas B-site dilution results in (Co2+)A[Mn3+1−xBZn2+xBCo3+]BO4−...

Full description

Saved in:
Bibliographic Details
Main Authors: Tiwari, Nidhi, Pramanik, P., Joshi, D. C., Sarkar, T., Pittala, S., Salman, O. O., Manga, M.-M., Thota, S.
Other Authors: Energy Research Institute @ NTU (ERI@N)
Format: Article
Language:English
Published: 2019
Subjects:
Online Access:https://hdl.handle.net/10356/86246
http://hdl.handle.net/10220/49268
Tags: Add Tag
No Tags, Be the first to tag this record!
Institution: Nanyang Technological University
Language: English
id sg-ntu-dr.10356-86246
record_format dspace
spelling sg-ntu-dr.10356-862462021-01-05T07:35:12Z Cationic distribution, exchange interactions, and relaxation dynamics in Zn-diluted MnCo2O4 nanostructures Tiwari, Nidhi Pramanik, P. Joshi, D. C. Sarkar, T. Pittala, S. Salman, O. O. Manga, M.-M. Thota, S. Energy Research Institute @ NTU (ERI@N) Cationic Distribution Exchange Interactions Science::Physics We report an experimental investigation of the electronic structure and magnetic properties of bulk and nanosized MnCo2O4 diluted with Zn. The cationic distribution for tetrahedral A-site dilution is (Co2+1−yAZn2+yA)A[Mn3+Co3+]BO4±δ, whereas B-site dilution results in (Co2+)A[Mn3+1−xBZn2+xBCo3+]BO4−δ. The strength of exchange interaction Jij between the magnetic ions in a bulk spinel lattice decreases by ∼15% for A-site dilution relative to the undiluted compound; however, B-site dilution results in an enhancement in Jij by 17%. The frequency and temperature dependence of dynamic-susceptibility [χac(f,T)] studies of nanostructured compounds reveals the existence of spin-glass like behavior below the freezing temperature TF∼125.7K (for xB=0.2) and 154.3 K (yA=0.1). Relaxation time τ follows the Power-Law variation with a dynamical critical exponent zν=6.17 and microscopic spin relaxation time τo=4.4×10−15s for xB=0.2 (for yA=0.1, zν=5.2 and τo=5.4×10−13s). The amplitude and peak position in χac(T) decreases with an increase in the DC bias field, which indicates that the spin-glass phase can survive in the presence of low fields forming a critical line with an exponent 2/3. This behavior is similar to the de Almeida-Thouless (AT-line) analysis in the T-H phase diagram which supports the existence of spin-glass like behavior below TF in these Zn diluted spinels. Published version 2019-07-11T01:33:48Z 2019-12-06T16:18:48Z 2019-07-11T01:33:48Z 2019-12-06T16:18:48Z 2019 Journal Article Pramanik, P., Joshi, D. C., Tiwari, N., Sarkar, T., Pittala, S., Salman, O. O., . . . Thota, S. (2019). Cationic distribution, exchange interactions, and relaxation dynamics in Zn-diluted MnCo2O4 nanostructures. Journal of Applied Physics, 125(12), 124302-. doi:10.1063/1.5079800 0021-8979 https://hdl.handle.net/10356/86246 http://hdl.handle.net/10220/49268 10.1063/1.5079800 en Journal of Applied Physics © 2019 The Author(s). All rights reserved. This paper was published by AIP in Journal of Applied Physics and is made available with permission of The Author(s). 11 p. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Cationic Distribution
Exchange Interactions
Science::Physics
spellingShingle Cationic Distribution
Exchange Interactions
Science::Physics
Tiwari, Nidhi
Pramanik, P.
Joshi, D. C.
Sarkar, T.
Pittala, S.
Salman, O. O.
Manga, M.-M.
Thota, S.
Cationic distribution, exchange interactions, and relaxation dynamics in Zn-diluted MnCo2O4 nanostructures
description We report an experimental investigation of the electronic structure and magnetic properties of bulk and nanosized MnCo2O4 diluted with Zn. The cationic distribution for tetrahedral A-site dilution is (Co2+1−yAZn2+yA)A[Mn3+Co3+]BO4±δ, whereas B-site dilution results in (Co2+)A[Mn3+1−xBZn2+xBCo3+]BO4−δ. The strength of exchange interaction Jij between the magnetic ions in a bulk spinel lattice decreases by ∼15% for A-site dilution relative to the undiluted compound; however, B-site dilution results in an enhancement in Jij by 17%. The frequency and temperature dependence of dynamic-susceptibility [χac(f,T)] studies of nanostructured compounds reveals the existence of spin-glass like behavior below the freezing temperature TF∼125.7K (for xB=0.2) and 154.3 K (yA=0.1). Relaxation time τ follows the Power-Law variation with a dynamical critical exponent zν=6.17 and microscopic spin relaxation time τo=4.4×10−15s for xB=0.2 (for yA=0.1, zν=5.2 and τo=5.4×10−13s). The amplitude and peak position in χac(T) decreases with an increase in the DC bias field, which indicates that the spin-glass phase can survive in the presence of low fields forming a critical line with an exponent 2/3. This behavior is similar to the de Almeida-Thouless (AT-line) analysis in the T-H phase diagram which supports the existence of spin-glass like behavior below TF in these Zn diluted spinels.
author2 Energy Research Institute @ NTU (ERI@N)
author_facet Energy Research Institute @ NTU (ERI@N)
Tiwari, Nidhi
Pramanik, P.
Joshi, D. C.
Sarkar, T.
Pittala, S.
Salman, O. O.
Manga, M.-M.
Thota, S.
format Article
author Tiwari, Nidhi
Pramanik, P.
Joshi, D. C.
Sarkar, T.
Pittala, S.
Salman, O. O.
Manga, M.-M.
Thota, S.
author_sort Tiwari, Nidhi
title Cationic distribution, exchange interactions, and relaxation dynamics in Zn-diluted MnCo2O4 nanostructures
title_short Cationic distribution, exchange interactions, and relaxation dynamics in Zn-diluted MnCo2O4 nanostructures
title_full Cationic distribution, exchange interactions, and relaxation dynamics in Zn-diluted MnCo2O4 nanostructures
title_fullStr Cationic distribution, exchange interactions, and relaxation dynamics in Zn-diluted MnCo2O4 nanostructures
title_full_unstemmed Cationic distribution, exchange interactions, and relaxation dynamics in Zn-diluted MnCo2O4 nanostructures
title_sort cationic distribution, exchange interactions, and relaxation dynamics in zn-diluted mnco2o4 nanostructures
publishDate 2019
url https://hdl.handle.net/10356/86246
http://hdl.handle.net/10220/49268
_version_ 1688665716817920000