Unravelling the Elusive Antiferromagnetic Order in Wurtzite and Zinc Blende CoO Polymorph Nanoparticles

Alejandro G. Roca; Igor V. Golosovsky; Elin Winkler; Alberto López-Ortega; Marta Estrader; Roberto D. Zysler; María Dolors Baró; Josep Nogués

doi:https://doi.org/10.1002/smll.201703963

Unravelling the Elusive Antiferromagnetic Order in Wurtzite and Zinc Blende CoO Polymorph Nanoparticles

Alejandro G. Roca, Igor V. Golosovsky, Elin Winkler, Alberto López-Ortega, Marta Estrader, Roberto D. Zysler, María Dolors Baró, Josep Nogués

Department of Physics

Research output: Contribution to journal › Article › Research › peer-review

11 Citations (Scopus)

Abstract

© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Although cubic rock salt-CoO has been extensively studied, the magnetic properties of the main nanoscale CoO polymorphs (hexagonal wurtzite and cubic zinc blende structures) are rather poorly understood. Here, a detailed magnetic and neutron diffraction study on zinc blende and wurtzite CoO nanoparticles is presented. The zinc blende-CoO phase is antiferromagnetic with a 3rd type structure in a face-centered cubic lattice and a Néel temperature of TN (zinc-blende) ≈225 K. Wurtzite-CoO also presents an antiferromagnetic order, TN (wurtzite) ≈109 K, although much more complex, with a 2nd type order along the c-axis but an incommensurate order along the y-axis. Importantly, the overall magnetic properties are overwhelmed by the uncompensated spins, which confer the system a ferromagnetic-like behavior even at room temperature.

Original language	English
Article number	1703963
Journal	Small
Volume	14
Issue number	15
DOIs	https://doi.org/10.1002/smll.201703963
Publication status	Published - 12 Apr 2018

Keywords

CoO wurtzite
CoO zinc blende
antiferromagnets
incommensurate structures
uncompensated spins

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https://ddd.uab.cat/record/214196

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title = "Unravelling the Elusive Antiferromagnetic Order in Wurtzite and Zinc Blende CoO Polymorph Nanoparticles",

abstract = "{\textcopyright} 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Although cubic rock salt-CoO has been extensively studied, the magnetic properties of the main nanoscale CoO polymorphs (hexagonal wurtzite and cubic zinc blende structures) are rather poorly understood. Here, a detailed magnetic and neutron diffraction study on zinc blende and wurtzite CoO nanoparticles is presented. The zinc blende-CoO phase is antiferromagnetic with a 3rd type structure in a face-centered cubic lattice and a N{\'e}el temperature of TN (zinc-blende) ≈225 K. Wurtzite-CoO also presents an antiferromagnetic order, TN (wurtzite) ≈109 K, although much more complex, with a 2nd type order along the c-axis but an incommensurate order along the y-axis. Importantly, the overall magnetic properties are overwhelmed by the uncompensated spins, which confer the system a ferromagnetic-like behavior even at room temperature.",

keywords = "CoO wurtzite, CoO zinc blende, antiferromagnets, incommensurate structures, uncompensated spins",

author = "Roca, {Alejandro G.} and Golosovsky, {Igor V.} and Elin Winkler and Alberto L{\'o}pez-Ortega and Marta Estrader and Zysler, {Roberto D.} and Bar{\'o}, {Mar{\'i}a Dolors} and Josep Nogu{\'e}s",

year = "2018",

month = apr,

day = "12",

doi = "https://doi.org/10.1002/smll.201703963",

language = "English",

volume = "14",

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TY - JOUR

T1 - Unravelling the Elusive Antiferromagnetic Order in Wurtzite and Zinc Blende CoO Polymorph Nanoparticles

AU - Roca, Alejandro G.

AU - Golosovsky, Igor V.

AU - Winkler, Elin

AU - López-Ortega, Alberto

AU - Estrader, Marta

AU - Zysler, Roberto D.

AU - Baró, María Dolors

AU - Nogués, Josep

PY - 2018/4/12

Y1 - 2018/4/12

N2 - © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Although cubic rock salt-CoO has been extensively studied, the magnetic properties of the main nanoscale CoO polymorphs (hexagonal wurtzite and cubic zinc blende structures) are rather poorly understood. Here, a detailed magnetic and neutron diffraction study on zinc blende and wurtzite CoO nanoparticles is presented. The zinc blende-CoO phase is antiferromagnetic with a 3rd type structure in a face-centered cubic lattice and a Néel temperature of TN (zinc-blende) ≈225 K. Wurtzite-CoO also presents an antiferromagnetic order, TN (wurtzite) ≈109 K, although much more complex, with a 2nd type order along the c-axis but an incommensurate order along the y-axis. Importantly, the overall magnetic properties are overwhelmed by the uncompensated spins, which confer the system a ferromagnetic-like behavior even at room temperature.

AB - © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Although cubic rock salt-CoO has been extensively studied, the magnetic properties of the main nanoscale CoO polymorphs (hexagonal wurtzite and cubic zinc blende structures) are rather poorly understood. Here, a detailed magnetic and neutron diffraction study on zinc blende and wurtzite CoO nanoparticles is presented. The zinc blende-CoO phase is antiferromagnetic with a 3rd type structure in a face-centered cubic lattice and a Néel temperature of TN (zinc-blende) ≈225 K. Wurtzite-CoO also presents an antiferromagnetic order, TN (wurtzite) ≈109 K, although much more complex, with a 2nd type order along the c-axis but an incommensurate order along the y-axis. Importantly, the overall magnetic properties are overwhelmed by the uncompensated spins, which confer the system a ferromagnetic-like behavior even at room temperature.

KW - CoO wurtzite

KW - CoO zinc blende

KW - antiferromagnets

KW - incommensurate structures

KW - uncompensated spins

U2 - https://doi.org/10.1002/smll.201703963

DO - https://doi.org/10.1002/smll.201703963

M3 - Article

SN - 1613-6810

VL - 14

JO - Small

JF - Small

IS - 15

M1 - 1703963

ER -

Unravelling the Elusive Antiferromagnetic Order in Wurtzite and Zinc Blende CoO Polymorph Nanoparticles

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Keywords

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