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Tykhonenko-Polishchuk, Yuliya
Publications (2 of 2) Show all publications
Polishchuk, D., Tykhonenko-Polishchuk, Y., Holmgren, E., Kravets, A., Tovstolytkin, A. I. & Korenivski, V. (2018). Giant magnetocaloric effect driven by indirect exchange in magnetic multilayers. PHYSICAL REVIEW MATERIALS, 2(11), Article ID 114402.
Open this publication in new window or tab >>Giant magnetocaloric effect driven by indirect exchange in magnetic multilayers
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2018 (English)In: PHYSICAL REVIEW MATERIALS, ISSN 2475-9953, Vol. 2, no 11, article id 114402Article in journal (Refereed) Published
Abstract [en]

Indirect exchange coupling in magnetic multilayers, also known as the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction, is highly effective in controlling the interlayer alignment of the magnetization. This coupling is typically fixed at the stage of the multilayer fabrication and does not allow ex situ control needed for device applications. In addition to the orientational control, it is highly desirable to also control the magnitude of the intralayer magnetization, ideally, being able to switch it on/off by switching the relevant RKKY coupling. Here we demonstrate a magnetic multilayer material incorporating thermally and field-controlled RKKY exchange, focused on a dilute ferromagnetic alloy layer and driving it though its Curie transition. Such on/off magnetization switching of a thin ferromagnet, performed repeatedly and fully reproducibly within a low-field sweep, results in a giant magnetocaloric effect, with an estimated isothermal entropy change of Delta S approximate to -10 mJ cm(-3) K(-1 )under an external field of similar to 10 mT, which greatly exceeds the performance of the best rare-earth based materials used in the adiabatic-demagnetization refrigeration systems.

Place, publisher, year, edition, pages
AMER PHYSICAL SOC, 2018
National Category
Nano Technology
Identifiers
urn:nbn:se:kth:diva-239779 (URN)10.1103/PhysRevMaterials.2.114402 (DOI)000450572600002 ()2-s2.0-85060615826 (Scopus ID)
Note

QC 20190108

Available from: 2019-01-08 Created: 2019-01-08 Last updated: 2019-04-29Bibliographically approved
Polishchuk, D., Tykhonenko-Polishchuk, Y., Borynskyi, V., Kravets, A., Tovstolytkin, A. & Korenivski, V. (2018). Magnetic Hysteresis in Nanostructures with Thermally Controlled RKKY Coupling. Nanoscale Research Letters, 13, Article ID 245.
Open this publication in new window or tab >>Magnetic Hysteresis in Nanostructures with Thermally Controlled RKKY Coupling
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2018 (English)In: Nanoscale Research Letters, ISSN 1931-7573, E-ISSN 1556-276X, Vol. 13, article id 245Article in journal (Refereed) Published
Abstract [en]

Mechanisms of the recently demonstrated ex-situ thermal control of the indirect exchange coupling in magnetic multilayer are discussed for different designs of the spacer layer. Temperature-induced changes in the hysteresis of magnetization are shown to be associated with different types of competing interlayer exchange interactions. Theoretical analysis indicates that the measured step-like shape and hysteresis of the magnetization loops is due to local in-plane magnetic anisotropy of nano-crystallites within the strongly ferromagnetic films. Comparison of the experiment and theory is used to contrast the mechanisms of the magnetization switching based on the competition of (i) indirect (RKKY) and direct (non-RKKY) interlayer exchange interactions as well as (ii) indirect ferromagnetic and indirect antiferromagnetic (both of RKKY type) interlayer exchange. These results, detailing the rich magnetic phase space of the system, should help enable the practical use of RKKY for thermally switching the magnetization in magnetic multilayers.

Place, publisher, year, edition, pages
Springer, 2018
Keywords
Magnetic multilayers, Indirect exchange coupling, Magnetization switching, Magnetic coercivity, Thermo-magnetic effects
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-234599 (URN)10.1186/s11671-018-2669-0 (DOI)000443039100003 ()30136038 (PubMedID)2-s2.0-85052080291 (Scopus ID)
Note

QC 20180914

Available from: 2018-09-14 Created: 2018-09-14 Last updated: 2018-09-14Bibliographically approved
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