Room-Temperature Insulating Ferromagnetic (Ni,Co)1+2                             xTi1−                             xO3 Thin Films

Yukari Fujioka; Johannes Frantti; Christopher Rouleau; Alexander Puretzky; Zheng Gai; Nickolay Lavrik; Andreas Herklotz; Ilia Ivanov; Harry Meyer

doi:10.1002/andp.201900299

Room-Temperature Insulating Ferromagnetic (Ni,Co)₁₊₂ _xTi₁₋ _xO₃ Thin Films

Yukari Fujioka, Johannes Frantti, Christopher Rouleau, Alexander Puretzky, Zheng Gai, Nickolay Lavrik, Andreas Herklotz, Ilia Ivanov, Harry Meyer

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

8 Scopus citations

Abstract

Insulating uniaxial room-temperature ferromagnets are a prerequisite for commonplace spin wave-based devices, the obstacle in contemporary ferromagnets being the coupling of ferromagnetism with large conductivity. It is shown that the uniaxial A_{1 + 2} _xTi⁴⁺ _{1 −} _xO₃ (ATO), A = Ni²⁺,Co²⁺, and 0.6 < x ≤ 1, thin films are electrically insulating ferromagnets already at room temperature. The octahedra network of the ATO and the corundum and ilmenite structures are the same yet different octahedra-filling proved to be a route to switch from the antiferromagnetic to ferromagnetic regime. Octahedra can continuously be filled up to x = 1, or vacated (−0.24 < x < 0) in the ATO structure. TiO-layers, which separate the ferromagnetic (Ni,Co)O-layers and intermediate the antiferromagnetic coupling between the ferromagnetic layers in the NiTiO₃ and CoTiO₃ ilmenites, can continuously be replaced by (Ni,Co)O-layers to convert the ATO-films to ferromagnetic insulator with abundant direct cation interactions.

Original language	English
Article number	1900299
Journal	Annalen der Physik
Volume	531
Issue number	11
DOIs	https://doi.org/10.1002/andp.201900299
State	Published - Nov 1 2019

Bibliographical note

Publisher Copyright:
© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Funding

All experimental work was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility. The project was financially supported by Reciprocal Engineering – RE Ltd. and the Business Finland. The authors would like to thank reviewers for constructive suggestions.

Funders	Funder number
Office of Science

Keywords

corundum compounds
ilmenites
insulating ferromagnet
nickel cobalt titanates
thin films

Access to Document

10.1002/andp.201900299

Cite this

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title = "Room-Temperature Insulating Ferromagnetic (Ni,Co)1+2 xTi1− xO3 Thin Films",

abstract = "Insulating uniaxial room-temperature ferromagnets are a prerequisite for commonplace spin wave-based devices, the obstacle in contemporary ferromagnets being the coupling of ferromagnetism with large conductivity. It is shown that the uniaxial A1 + 2 xTi4+ 1 − xO3 (ATO), A = Ni2+,Co2+, and 0.6 < x ≤ 1, thin films are electrically insulating ferromagnets already at room temperature. The octahedra network of the ATO and the corundum and ilmenite structures are the same yet different octahedra-filling proved to be a route to switch from the antiferromagnetic to ferromagnetic regime. Octahedra can continuously be filled up to x = 1, or vacated (−0.24 < x < 0) in the ATO structure. TiO-layers, which separate the ferromagnetic (Ni,Co)O-layers and intermediate the antiferromagnetic coupling between the ferromagnetic layers in the NiTiO3 and CoTiO3 ilmenites, can continuously be replaced by (Ni,Co)O-layers to convert the ATO-films to ferromagnetic insulator with abundant direct cation interactions.",

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AU - Puretzky, Alexander

AU - Gai, Zheng

AU - Lavrik, Nickolay

AU - Herklotz, Andreas

AU - Ivanov, Ilia

AU - Meyer, Harry

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