Spontaneous exchange bias formation driven by a structural phase transition in the antiferromagnetic material

TY - JOUR

T1 - Spontaneous exchange bias formation driven by a structural phase transition in the antiferromagnetic material

AU - Migliorini, A

AU - Kuerbanjiang, B

AU - Huminiuc, T

AU - Kepaptsoglou, D

AU - Muñoz, M

AU - Cuñado, J L F

AU - Camarero, J

AU - Aroca, C

AU - Vallejo-Fernández, G

AU - Lazarov, V K

AU - Prieto, J L

N1 - © 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details.

PY - 2018/1/1

Y1 - 2018/1/1

N2 - Most of the magnetic devices in advanced electronics rely on the exchange bias effect, a magnetic interaction that couples a ferromagnetic and an antiferromagnetic material, resulting in a unidirectional displacement of the ferromagnetic hysteresis loop by an amount called the 'exchange bias field'. Setting and optimizing exchange bias involves cooling through the Néel temperature of the antiferromagnetic material in the presence of a magnetic field. Here we demonstrate an alternative process for the generation of exchange bias. In IrMn/FeCo bilayers, a structural phase transition in the IrMn layer develops at room temperature, exchange biasing the FeCo layer as it propagates. Once the process is completed, the IrMn layer contains very large single-crystal grains, with a large density of structural defects within each grain, which are promoted by the FeCo layer. The magnetic characterization indicates that these structural defects in the antiferromagnetic layer are behind the resulting large value of the exchange bias field and its good thermal stability. This mechanism for establishing the exchange bias in such a system can contribute towards the clarification of fundamental aspects of this exchange interaction.

AB - Most of the magnetic devices in advanced electronics rely on the exchange bias effect, a magnetic interaction that couples a ferromagnetic and an antiferromagnetic material, resulting in a unidirectional displacement of the ferromagnetic hysteresis loop by an amount called the 'exchange bias field'. Setting and optimizing exchange bias involves cooling through the Néel temperature of the antiferromagnetic material in the presence of a magnetic field. Here we demonstrate an alternative process for the generation of exchange bias. In IrMn/FeCo bilayers, a structural phase transition in the IrMn layer develops at room temperature, exchange biasing the FeCo layer as it propagates. Once the process is completed, the IrMn layer contains very large single-crystal grains, with a large density of structural defects within each grain, which are promoted by the FeCo layer. The magnetic characterization indicates that these structural defects in the antiferromagnetic layer are behind the resulting large value of the exchange bias field and its good thermal stability. This mechanism for establishing the exchange bias in such a system can contribute towards the clarification of fundamental aspects of this exchange interaction.

KW - Journal Article

UR - http://www.scopus.com/inward/record.url?scp=85038568812&partnerID=8YFLogxK

U2 - 10.1038/nmat5030

DO - 10.1038/nmat5030

M3 - Article

C2 - 29180774

VL - 17

SP - 28

EP - 35

JO - Nature Materials

JF - Nature Materials

SN - 1476-1122

IS - 1

ER -