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Title: Observation of longitudinal spin-Seebeck effect in cobalt-ferrite epitaxial thin films

Abstract

The longitudinal spin-Seebeck effect (LSSE) has been investigated in cobalt ferrite (CFO), an exceptionally hard magnetic spinel ferrite. A bilayer of a polycrystalline Pt and an epitaxially-strained CFO(110) exhibiting an in-plane uniaxial anisotropy was prepared by reactive rf sputtering technique. Thermally generated spin voltage in the CFO layer was measured via the inverse spin-Hall effect in the Pt layer. External-magnetic-field (H) dependence of the LSSE voltage (V{sub LSSE}) in the Pt/CFO(110) sample with H ∥ [001] was found to exhibit a hysteresis loop with a high squareness ratio and high coercivity, while that with H∥[11{sup -}0] shows a nearly closed loop, reflecting the different anisotropies induced by the epitaxial strain. The magnitude of V{sub LSSE} has a linear relationship with the temperature difference (ΔT), giving the relatively large V{sub LSSE} /ΔT of about 3 μV/K for CFO(110) which was kept even at zero external field.

Authors:
 [1];  [2];  [3];  [2];  [3];  [2];  [2]; ; ; ;  [4];  [1];  [2];  [2];  [2]
  1. WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan)
  2. (Japan)
  3. Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577 (Japan)
  4. Institute of Applied Physics, University of Tsukuba, Tsukuba 305-8573 (Japan)
Publication Date:
OSTI Identifier:
22488564
Resource Type:
Journal Article
Journal Name:
AIP Advances
Additional Journal Information:
Journal Volume: 5; Journal Issue: 5; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 2158-3226
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANISOTROPY; COBALT; COERCIVE FORCE; ELECTRIC POTENTIAL; EPITAXY; FERRITE; FERRITES; HALL EFFECT; HYSTERESIS; MAGNETIC FIELDS; POLYCRYSTALS; SEEBECK EFFECT; SPIN; SPINELS; SPUTTERING; STRAINS; THIN FILMS

Citation Formats

Niizeki, Tomohiko, E-mail: t-niizeki@imr.tohoku.ac.jp, Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577, Kikkawa, Takashi, Institute for Materials Research, Tohoku University, Sendai 980-8577, Uchida, Ken-ichi, E-mail: kuchida@imr.tohoku.ac.jp, Institute for Materials Research, Tohoku University, Sendai 980-8577, PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Oka, Mineto, Suzuki, Kazuya Z., Yanagihara, Hideto, Kita, Eiji, Saitoh, Eiji, Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577, Institute for Materials Research, Tohoku University, Sendai 980-8577, and Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195. Observation of longitudinal spin-Seebeck effect in cobalt-ferrite epitaxial thin films. United States: N. p., 2015. Web. doi:10.1063/1.4916978.
Niizeki, Tomohiko, E-mail: t-niizeki@imr.tohoku.ac.jp, Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577, Kikkawa, Takashi, Institute for Materials Research, Tohoku University, Sendai 980-8577, Uchida, Ken-ichi, E-mail: kuchida@imr.tohoku.ac.jp, Institute for Materials Research, Tohoku University, Sendai 980-8577, PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Oka, Mineto, Suzuki, Kazuya Z., Yanagihara, Hideto, Kita, Eiji, Saitoh, Eiji, Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577, Institute for Materials Research, Tohoku University, Sendai 980-8577, & Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195. Observation of longitudinal spin-Seebeck effect in cobalt-ferrite epitaxial thin films. United States. doi:10.1063/1.4916978.
Niizeki, Tomohiko, E-mail: t-niizeki@imr.tohoku.ac.jp, Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577, Kikkawa, Takashi, Institute for Materials Research, Tohoku University, Sendai 980-8577, Uchida, Ken-ichi, E-mail: kuchida@imr.tohoku.ac.jp, Institute for Materials Research, Tohoku University, Sendai 980-8577, PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Oka, Mineto, Suzuki, Kazuya Z., Yanagihara, Hideto, Kita, Eiji, Saitoh, Eiji, Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577, Institute for Materials Research, Tohoku University, Sendai 980-8577, and Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195. Fri . "Observation of longitudinal spin-Seebeck effect in cobalt-ferrite epitaxial thin films". United States. doi:10.1063/1.4916978.
@article{osti_22488564,
title = {Observation of longitudinal spin-Seebeck effect in cobalt-ferrite epitaxial thin films},
author = {Niizeki, Tomohiko, E-mail: t-niizeki@imr.tohoku.ac.jp and Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577 and Kikkawa, Takashi and Institute for Materials Research, Tohoku University, Sendai 980-8577 and Uchida, Ken-ichi, E-mail: kuchida@imr.tohoku.ac.jp and Institute for Materials Research, Tohoku University, Sendai 980-8577 and PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 and Oka, Mineto and Suzuki, Kazuya Z. and Yanagihara, Hideto and Kita, Eiji and Saitoh, Eiji and Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577 and Institute for Materials Research, Tohoku University, Sendai 980-8577 and Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195},
abstractNote = {The longitudinal spin-Seebeck effect (LSSE) has been investigated in cobalt ferrite (CFO), an exceptionally hard magnetic spinel ferrite. A bilayer of a polycrystalline Pt and an epitaxially-strained CFO(110) exhibiting an in-plane uniaxial anisotropy was prepared by reactive rf sputtering technique. Thermally generated spin voltage in the CFO layer was measured via the inverse spin-Hall effect in the Pt layer. External-magnetic-field (H) dependence of the LSSE voltage (V{sub LSSE}) in the Pt/CFO(110) sample with H ∥ [001] was found to exhibit a hysteresis loop with a high squareness ratio and high coercivity, while that with H∥[11{sup -}0] shows a nearly closed loop, reflecting the different anisotropies induced by the epitaxial strain. The magnitude of V{sub LSSE} has a linear relationship with the temperature difference (ΔT), giving the relatively large V{sub LSSE} /ΔT of about 3 μV/K for CFO(110) which was kept even at zero external field.},
doi = {10.1063/1.4916978},
journal = {AIP Advances},
issn = {2158-3226},
number = 5,
volume = 5,
place = {United States},
year = {2015},
month = {5}
}